Biomass-Derived Biochar for The Removal of Textile Dyes from Aqueous Solutions: A Review

It may state two separate claims as one.

The chitosan-impregnated sugarcane bagasse biochar had a maximum adsorption capacity of 170 mg/g for Congo Red and removed more than 95 % of dye at pH 3.

“The chitosan-impregnated sugarcane bagasse biochar had a maximum adsorption capacity of 170 mg/g for Congo Red and removed more than 95 % of dye at pH 3 [6].”

• cites [6] Akl, 2024, Scientific Reports sourceDisputed

  The Conclusion (page unavailable) identifies the studied adsorbent as kitchen-waste-derived biochar, not chitosan-impregnated sugarcane bagasse biochar. It reports maximum adsorption capacities of 30.40 mg/g for methylene blue and 25.15 mg/g for methyl orange, not 170 mg/g for Congo Red; it does not report the claimed removal at pH 3. (LLM, conf=0.88)

  Checked by a reasoning model — may be wrong.

  Experimental — accuracy not yet measured

It may state two separate claims as one.

The same study reported that methyl orange followed a Freundlich isotherm, suggesting multilayer adsorption on heterogeneous sites.

“The same study reported that methyl orange followed a Freundlich isotherm, suggesting multilayer adsorption on heterogeneous sites.”

• cites [1] Eleryan, 2024, Scientific Reports sourceDisputed

  The Results and discussion section (‘Adsorption isotherms’; page unavailable) studies Acid Red 73, not methyl orange, and says its adsorption data fit the Langmuir model, indicating a homogeneous surface and monolayer adsorption. Although the paper describes Freundlich as a model for heterogeneous, multilayer adsorption, it does not report that result for the dye studied. (LLM, conf=0.90)

  Checked by a reasoning model — may be wrong.

  Experimental — accuracy not yet measured

It may state two separate claims as one.

pH influences adsorption: crystal violet removal increased up to pH 6-7 but decreased at highly alkaline or acidic conditions.

“The same study showed that pH influences adsorption: crystal violet removal increased up to pH 6-7 but decreased at highly alkaline or acidic conditions [14].”

• cites [14] Tang, 2025, Food Chemistry X sourceDisputed

  The Results and discussion (Adsorption capacity analysis) report that crystal violet adsorption efficiency gradually improved as pH rose from 3.0 to 9.0. Low-pH inhibition agrees with the claim, but the reported increase through pH 9 contradicts its proposed peak at pH 6–7 and subsequent decline. The paper did not test pH above 9. (LLM, conf=0.90)

  Checked by a reasoning model — may be wrong.

  Experimental — accuracy not yet measured

It may state two separate claims as one.

Increasing pyrolysis temperature from 200 °C to 600 °C increases specific surface area but decreases oxygen-containing functional groups; at temperatures above 700 °C surface area may continue to increase but many functional groups are lost, reducing adsorption of crystal violet.

“Tang et al. reported that increasing pyrolysis temperature from 200 °C to 600 °C increases specific surface area but decreases oxygen-containing functional groups; at temperatures above 700 °C surface area may continue to increase but many functional groups are lost, reducing adsorption of crystal violet [14].”

• cites [14] Tang, 2025, Food Chemistry X sourceDisputed

  Split into 2 atoms — 0 confirmed, 1 partially supported, 1 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

  Checked by a reasoning model — may be wrong.

  Experimental — accuracy not yet measured

It may state two separate claims as one.

Applying biochar to saline soils improved wheat growth and chlorophyll content.

“Applying biochar to saline soils improved wheat growth and chlorophyll content [10].”

• cites [10] Kataya, 2025, Materials sourceSupported

It may state two separate claims as one.

Biological treatment is slow and often ineffective for synthetic dyes because of their complex aromatic structures.

“Biological treatment is slow and often ineffective for synthetic dyes because of their complex aromatic structures [6]”

• cites [6] Akl, 2024, Scientific Reports sourcePartly supported

  The Introduction says synthetic dyes’ high chemical stability and low biodegradability limit the effectiveness of biological treatments. It mentions long treatment times for dye-removal methods generally, but does not specifically say biological treatment is slow. Its discussion of aromatic rings concerns adsorption, not why biological treatment is ineffective. (LLM, conf=0.87)

  Experimental — accuracy not yet measured

It may state two separate claims as one.

Sulfuric-acid-treated kitchen-waste biochar achieved 100 % removal of crystal violet with a capacity of 450 mg/g.

“Sulfuric-acid-treated kitchen-waste biochar achieved 100 % removal of crystal violet with a capacity of 450 mg/g [11].”

• cites [11] Rashidi N. A. and Yusup S., A mini review of biochar synthesis, characterization, and related standardization and legislation, IntechOpen eBooks, https://doi.org/10.5772/intechopen.92621 sourceCould not verify

  The color/dyes removal table (page unavailable) lists other feedstocks and dyes, but not sulfuric-acid-treated kitchen-waste biochar or crystal violet. Searches for those terms and 450 mg/g found no passage reporting the claimed 100% removal or capacity. (LLM, conf=0.76)

  Experimental — accuracy not yet measured

It may state two separate claims as one.

The diversity of dye structures explains why different dyes interact differently with adsorbents and why no single treatment can remove all dyes effectively.

“The diversity of structures explains why different dyes interact differently with adsorbents and why no single treatment can remove all dyes effectively [1].”

• cites [1] Eleryan, 2024, Scientific Reports sourcePartly supported

  The Results and discussion section (Adsorption mechanism of AR73 Dye by MBCOT; page unavailable) describes negatively charged AR73 binding to a positively charged surface and contrasts this with cationic dyes binding to negatively charged sites at alkaline pH. This supports different adsorption interactions, but the paper does not establish that structural diversity explains those differences or that no single treatment can remove all dyes effectively. (LLM, conf=0.79)

  Experimental — accuracy not yet measured

It may state two separate claims as one.

Sulfuric-acid-treated kitchen-waste biochar removed crystal violet dye and improved wheat growth under saline conditions.

“Sulfuric-acid-treated kitchen-waste biochar not only removed crystal violet dye but also improved wheat growth under saline conditions [10].”

• cites [10] Kataya, 2025, Materials sourcePartly supported

  The Conclusions report that sulfuric-acid-treated kitchen-waste biochar removed crystal violet, and Results §3.4 reports improved wheat growth with biochar under saline irrigation. But the soil-amendment method (§2.6) does not identify the biochar used for wheat as sulfuric-acid-treated, so the claim that this specific treatment produced both effects is not established. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

It may state two separate claims as one.

ZnCl2-activated dyeing sludge biochar showed high surface area (495 m2/g) and a maximum malachite green adsorption capacity of 224 mg/g.

“For example, ZnCl₂-activated dyeing sludge biochar showed high surface area (495 m²/g) and a maximum malachite green adsorption capacity of 224 mg/g [3].”

• cites [3] Qian W., Deng Y., Zhang Y., Li Y., Fang Y., Li X., Liang J. and Liu H., Dyeing sludge-derived biocha3r for efficient removal of malachite green from dyeing wastewater, Water Emerging Contaminants & Nanoplastics, https://doi.org/10.20517/wecn.2024.25 sourceSupported

It may state two separate claims as one.

Membrane filtration suffers from fouling, high capital cost and disposal of concentrate streams.

“Membrane filtration suffers from fouling, high capital cost and disposal of concentrate streams [2].”

• cites [2] Kataya, 2025, Scientific Reports sourcePartly supported

  The Introduction states that membrane technologies such as reverse osmosis suffer from fouling. It discusses high costs for treatment methods more generally, but does not identify high capital cost for membrane filtration or mention disposal of concentrate streams (no page number is provided in our copy). (LLM, conf=0.88)

  Experimental — accuracy not yet measured

It may state two separate claims as one.

ZnCl2 activation of dyeing sludge biochar produced a surface area of 495 m2/g and improved pore development.

“ZnCl₂ activation of dyeing sludge biochar produced a surface area of 495 m²/g and improved pore development [3].”

• cites [3] Qian W., Deng Y., Zhang Y., Li Y., Fang Y., Li X., Liang J. and Liu H., Dyeing sludge-derived biocha3r for efficient removal of malachite green from dyeing wastewater, Water Emerging Contaminants & Nanoplastics, https://doi.org/10.20517/wecn.2024.25 sourceSupported

It may state two separate claims as one.

The ash contributed to negatively charged sites to attract cationic dye molecules and increased pore size to promote adsorption of anionic dye molecules.

“the ash contributed to negatively charged sites to attract cationic dye molecules and increased pore size to promote adsorption of anionic dye molecules.”

• cites [17] Phuong, 2019, Desalination and Water Treatment sourcePartly supported

  The abstract (p. 1) reports negative charges in the biochars, electrostatic interaction with cationic dye, and dye transport through pores. It does not attribute the negative charges to ash or say that ash increased pore size to promote anionic-dye adsorption. (LLM, conf=0.82)

  Experimental — accuracy not yet measured

It may state two separate claims as one.

Despite its very low BET surface area (2.1 m2/g), PNS900 removed 100 % of the anthraquinone dye Remazol Brilliant Blue at pH 6.5, whereas SFS900 with 85.7 m2/g required a higher dosage to achieve the same removal.

“Despite its very low BET surface area (2.1 m²/g), PNS900 removed 100 % of the anthraquinone dye Remazol Brilliant Blue at pH 6.5, whereas SFS900 with 85.7 m²/g required a higher dosage to achieve the same removal [15].”

• cites [15] Sutradhar, 2024, Plants sourcePartly supported

  Section 2.4 reports BET surface areas of 2.1 m²/g for PNS900 and 85.7 m²/g for SFS900 and identifies RBB as an anthraquinone dye. Section 2.3 reports 100% RBB removal at 0.25 g of PNS900 versus 0.5 g of SFS900. Section 3 describes removal at neutral pH, but the passages found do not specify pH 6.5; Section 4.4 also gives no experimental pH. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

It may state two separate claims as one.

Adsorption of both types of dyes was affected by pH: alkaline environments promoted adsorption of cationic dye but inhibited adsorption of anionic dye.

“Adsorption of both types of dyes was affected by pH: alkaline environments promoted adsorption of cationic dye but inhibited adsorption of anionic dye.”

• cites [17] Phuong, 2019, Desalination and Water Treatment sourceSupported

It may state two separate claims as one.

π-π stacking, hydrogen bonding and anion-cation interactions contributed to dye binding.

“Mechanistic analysis suggested that π-π stacking, hydrogen bonding and anion-cation interactions contributed to dye binding [15].”

• cites [15] Sutradhar, 2024, Plants sourceSupported

It may state two separate claims as one.

Chitosan introduces amine groups that interact with anionic dyes and overcome the negative surface charge of pristine bagasse biochar.

“Chitosan introduces amine groups that interact with anionic dyes and overcome the negative surface charge of pristine bagasse biochar.”

• cites [6] Akl, 2024, Scientific Reports sourcePartly supported

  The Results and discussion section (Adsorption mechanisms exploration; page unavailable) says that a positively charged biochar surface attracts the negatively charged groups of anionic methyl orange. It does not say that chitosan introduces amine groups or that it overcomes the negative charge of pristine bagasse biochar. (LLM, conf=0.78)

  Experimental — accuracy not yet measured

It may state two separate claims as one.

All biomass is not the same; rice variety, production environment, and ash composition influence adsorption performance.

“This research demonstrates that all biomass is not the same; rice variety, production environment, and ash composition influence adsorption performance.[17]”

• cites [17] Phuong, 2019, Desalination and Water Treatment sourcePartly supported

  The abstract (p. 1) reports that biochars from Vietnamese IR50404 adsorbed both dyes more effectively than those from Japanese Koshihikari, supporting the point that rice residues differ in adsorption performance. The passages in our copy do not establish that production environment or ash composition influences that performance. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

It may state two separate claims as one.

Such modifications often require additional chemicals and may not be sustainable.

“However, such modifications often require additional chemicals and may not be sustainable.[12,13]”

• cites [12] Sohni, 2023, Industrial Crops and Products sourceNot checked yet
• cites [13] Yang, 2025, Separations sourceSupported

It may state two separate claims as one.

Biochars made using the IR50404 rice variety displayed 1.5 and 1.7 times greater adsorption of a cationic dye and anionic dye respectively compared with the Koshihikari biochar.

“Biochars made using the IR50404 rice variety displayed 1.5 and 1.7 times greater adsorption of a cationic dye and anionic dye respectively compared with the Koshihikari biochar.”

• cites [17] Phuong, 2019, Desalination and Water Treatment sourceSupported

It may state two separate claims as one.

Pyrolysis of peanut-shell feedstock at 900 °C (PNS900) produced biochar with higher nitrogen content and graphitic structures compared with sunflower shell biochar (SFS900); PNS900 contained 11.4 % more carbon and exhibited enhanced stability.

“The oil-seed shell study found that pyrolysis of peanut-shell feedstock at 900 °C (PNS900) produced biochar with higher nitrogen content and graphitic structures compared with sunflower shell biochar (SFS900); PNS900 contained 11.4 % more carbon and exhibited enhanced stability [15].”

• cites [15] Sutradhar, 2024, Plants sourcePartly supported

  Split into 2 atoms — 1 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

  Experimental — accuracy not yet measured

It may state two separate claims as one.

Equilibrium was reached within 5 min for PNS900 but took 30 min for SFS900, indicating faster diffusion and adsorption in the nitrogen-rich biochar.

“Equilibrium was reached within 5 min for PNS900 but took 30 min for SFS900, indicating faster diffusion and adsorption in the nitrogen-rich biochar [15].”

• cites [15] Sutradhar, 2024, Plants sourceSupported

It may state two separate claims as one.

The magnetite biochar composite and giant reed biochar both followed pseudo-second-order kinetics, suggesting chemisorption.

“For example, the magnetite biochar composite and giant reed biochar both followed pseudo-second-order kinetics [16], suggesting chemisorption.”

• cites [16] Teweldebrihan M. D., Grano M. A. and Dawit M., The Application of Magnetite Biochar Composite Derived from Parthenium Hysterophorus for the Adsorption of Methylene Blue from Aqueous Solution, SSRN Electronic Journal, https://doi.org/10.2139/ssrn.4758926 sourcePartly supported

  Section 3.6 (page unavailable) reports that adsorption onto the magnetite biochar composite was better described by pseudo-second-order kinetics and identifies chemisorption as the rate-limiting mechanism. The cited paper does not report a corresponding kinetic finding for giant reed biochar, so that part of the sentence is unsupported. (LLM, conf=0.89)

  Experimental — accuracy not yet measured

• AssumptionThe authors state this as an assumption: The pseudo-first-order model implies physisorption with diffusion control, while the pseudo-second-order model implies chemisorption where chemical bonding limits the rate.

It may state two separate claims as one.

The acid treatment increased surface area and introduced sulfonic groups that provide many active sites.

“The acid treatment increased surface area and introduced sulfonic groups that provide many active sites,”

• cites [10] Kataya, 2025, Materials sourcePartly supported

  The Results (§3.1) report that sulfuric-acid-treated biochar had a substantially larger surface area, and §3.3 says acid activation enhanced active sites. The paper reports sulfur incorporation in §3.1, but does not identify the resulting groups as sulfonic or say that sulfonic groups provide the active sites; §3.2 instead discusses –OH and –COOH groups. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

It may state two separate claims as one.

Nitrogen doping introduces pyridinic and graphitic nitrogen that enhance ππ interactions and electron donor-acceptor complexes.

“Nitrogen doping introduces pyridinic and graphitic nitrogen that enhance ππ interactions and electron donor-acceptor complexes [15].”

• cites [15] Sutradhar, 2024, Plants sourcePartly supported

  Sections 2.3 and 2.4 link increased nitrogen content to possible formation of pyridinic-N and graphitic-N, and describe their potential to enhance Lewis acid-base and π–π electron donor–acceptor interactions. The paper studies pyrolyzed seed-shell biochar, however, and does not establish that nitrogen doping introduced those groups or that the proposed enhancement occurred definitively. The indexed passages provide section labels but no page numbers. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

It may state two separate claims as one.

The mandarin-peel MBCOT biochar used triethylenetetramine to introduce amine groups and achieved high adsorption of Acid Red 73.

“The mandarin-peel MBCOT biochar used triethylenetetramine to introduce amine groups and achieved high adsorption of Acid Red 73 [1].”

• cites [1] Eleryan, 2024, Scientific Reports sourceSupported

It may state two separate claims as one.

Silver-modified biochar achieved similar removal but only 5 mg/g capacity.

“whereas silver-modified biochar achieved similar removal but only 5 mg/g capacity [10].”

• cites [10] Kataya, 2025, Materials sourceSupported

It may state two separate claims as one.

Metal-doped biochars such as magnetite composites have shown 99.99 % removal of methylene blue and good reusability.

“Metal-doped biochars such as magnetite composites have shown 99.99 % removal of methylene blue and good reusability [16].”

• cites [16] Teweldebrihan M. D., Grano M. A. and Dawit M., The Application of Magnetite Biochar Composite Derived from Parthenium Hysterophorus for the Adsorption of Methylene Blue from Aqueous Solution, SSRN Electronic Journal, https://doi.org/10.2139/ssrn.4758926 sourceSupported

It may state two separate claims as one.

Sulfuric-acid-treated kitchen-waste biochar achieved a capacity of 450 mg/g for crystal violet and 100 % removal efficiency.

“Sulfuric-acid-treated kitchen-waste biochar achieved a capacity of 450 mg/g for crystal violet and 100 % removal efficiency [10].”

• cites [10] Kataya, 2025, Materials sourceSupported

Probably not a substantial claim. It may state two separate claims as one.

The literature on biochar for dye removal is fragmented, with inconsistent experimental conditions, varying degrees of characterisation and little attention to real wastewater.

“However, the literature is fragmented, with inconsistent experimental conditions, varying degrees of characterisation and little attention to real wastewater.”

Probably not a substantial claim. The paper may give no reason why it holds.

Data from the literature show significant variation in adsorption capacities and removal efficiencies.

“Data from the literature show significant variation in adsorption capacities and removal efficiencies.”

It may state two separate claims as one.

Congo Red adsorption peaked at around 89 % and decreased above pH 5.5 because negatively charged biochar surfaces repel anionic dye molecules.

“The same article reported that Congo Red adsorption peaked at around 89 % and decreased above pH 5.5 because negatively charged biochar surfaces repel anionic dye molecules .”

• cites [15] Sutradhar, 2024, Plants sourceNot checked yet

  Checked before — its earlier verdict is held back until a new check runs.

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.

Biochar made from agricultural wastes can cost as little as USD 0.1-0.5 per kilogram depending on feedstock and production method.

“Biochar made from agricultural wastes can cost as little as USD 0.1-0.5 per kilogram depending on feedstock and production method.”

Probably not a substantial claim. The paper’s conclusions may not depend on it.

Biochar has been promoted as a low-cost alternative to activated carbon.

“It has been promoted as a low-cost alternative to activated carbon.[7,8]”

• cites [7] Varkolu, 2025, Catalysts sourceNot checked — no full text of the source
• cites [8] Aziz, 2024, Royal Society Open Science sourceNot checked yet

  Checked before — its earlier verdict is held back until a new check runs.

Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.

Using syngas to heat the reactor can close the energy loop and improve the overall sustainability of biochar production.

“Using syngas to heat the reactor can close the energy loop and improve the overall sustainability of biochar production.”

It may state two separate claims as one.

Biochar addition increased chlorophyll content and mitigated salt stress, demonstrating a circular benefit of using waste-derived adsorbents.

“Biochar addition increased chlorophyll content and mitigated salt stress, demonstrating a circular benefit of using waste-derived adsorbents.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.

The persistence of dyes in sediments and groundwater threatens drinking water resources and aquatic food webs.

“The persistence of dyes in sediments and groundwater threatens drinking water resources and aquatic food webs.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.

In pyrolysis of sewage sludge, the process also immobilises heavy metals and organic pollutants, reducing environmental risks while generating adsorbent.

“In pyrolysis of sewage sludge, the process also immobilises heavy metals and organic pollutants, reducing environmental risks while generating adsorbent.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.

Cationic dyes are attracted to negatively charged surfaces while anionic dyes require protonated or positively charged adsorbents.

“Cationic dyes are attracted to negatively charged surfaces while anionic dyes require protonated or positively charged adsorbents.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.

Pyrolysis is energy-intensive, and the economic viability depends on scale, feedstock logistics, energy recovery and co-product utilisation.

“However, pyrolysis is energy-intensive, and the economic viability depends on scale, feedstock logistics, energy recovery and co-product utilisation.”

Probably not a substantial claim. It may state two separate claims as one.

Converting dyeing sludge into biochar recovers resources and reduces the volume of hazardous waste disposed of.

“The OAE study argued that converting dyeing sludge into biochar recovers resources and reduces the volume of hazardous waste disposed of [3].”

• cites [3] Qian W., Deng Y., Zhang Y., Li Y., Fang Y., Li X., Liang J. and Liu H., Dyeing sludge-derived biocha3r for efficient removal of malachite green from dyeing wastewater, Water Emerging Contaminants & Nanoplastics, https://doi.org/10.20517/wecn.2024.25 sourceNot checked yet

  Checked before — its earlier verdict is held back until a new check runs.

Probably not a substantial claim. The paper’s conclusions may not depend on it.

The bio-oil and syngas can be used as fuels to offset the energy required for pyrolysis.

“The bio-oil and syngas can be used as fuels to offset the energy required for pyrolysis.”

Probably not a substantial claim. The paper may give no reason why it holds.

Recalcitrance of dyes arises from their aromatic and heterocyclic structures, resonance stabilisation and substituent groups that confer solubility and lightfastness.

“Recalcitrance of dyes arises from their aromatic and heterocyclic structures, resonance stabilisation and substituent groups that confer solubility and lightfastness.”

Probably not a substantial claim. The paper may give no reason why it holds.

Activated carbon typically costs USD 1-3 per kilogram.

“Activated carbon typically costs USD 1-3 per kilogram.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.

Hydrothermal carbonisation at 180 °C followed by activation can also produce efficient sorbents with lower energy consumption.

“Hydrothermal carbonisation at 180 °C followed by activation can also produce efficient sorbents with lower energy consumption.”

It may state two separate claims as one.

Biochar's performance can be enhanced by chemical activation, heteroatom doping and composite formation.

“Biochar's performance can be enhanced by chemical activation, heteroatom doping and composite formation.”

It may state two separate claims as one.

High surface area alone does not guarantee high adsorption capacity; the type and density of functional groups, aromaticity and electronic properties are equally important.

“High surface area alone does not guarantee high adsorption capacity; the type and density of functional groups, aromaticity and electronic properties are equally important.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.

Azo dyes contain azo linkages and often have sulfonic acid groups that increase solubility but reduce aromaticity.

“Azo dyes contain azo linkages and often have sulfonic acid groups that increase solubility but reduce aromaticity.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.

Some low-capacity adsorption processes may follow pseudo-first-order kinetics.

“In contrast, some low-capacity adsorption processes may follow pseudo-first-order kinetics.”

• AssumptionThe authors state this as an assumption: The pseudo-first-order model implies physisorption with diffusion control, while the pseudo-second-order model implies chemisorption where chemical bonding limits the rate.

It may state two separate claims as one.

In the dynamic removal study, methylene blue followed a Langmuir isotherm, indicating monolayer coverage.

“In the dynamic removal study, methylene blue followed a Langmuir isotherm, indicating monolayer coverage [1].”

• cites [1] Eleryan, 2024, Scientific Reports sourceNot checked yet

  Checked before — its earlier verdict is held back until a new check runs.

• AssumptionThe authors state this as an assumption: The Langmuir model assumes monolayer adsorption on homogeneous sites and finite adsorption capacity.

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.

Alkali activators such as KOH and NaOH create micro-mesoporous structures and oxygenated sites beneficial for anionic dyes.

“Alkali activators such as KOH and NaOH create micro-mesoporous structures and oxygenated sites beneficial for anionic dyes.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.

Natural organic matter can occlude pores and/or compete for adsorption sites.

“Also, natural organic matter can occlude pores and/or compete for adsorption sites.”

It may state two separate claims as one.

Universal mechanisms include electrostatic attraction, π-π electron donor-acceptor interactions, hydrogen bonding and pore filling.

“Universal mechanisms include electrostatic attraction, π-π electron donor-acceptor interactions, hydrogen bonding and pore filling.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.

Chemical activation and modification significantly improve performance but increase cost and potential environmental impact.

“Chemical activation and modification significantly improve performance but increase cost and potential environmental impact.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.

Metal impregnation with Fe, Zn, Cu or Mn introduces catalytic sites that can adsorb and oxidise dyes.

“Metal impregnation with Fe, Zn, Cu or Mn introduces catalytic sites that can adsorb and oxidise dyes.”

It may state two separate claims as one.

Acid treatments such as sulfuric acid, nitric acid or phosphoric acid increase surface area and introduce sulfonic or carboxylic groups that enhance cationic dye adsorption.

“treatments such as sulfuric acid, nitric acid or phosphoric acid increase surface area and introduce sulfonic or carboxylic groups that enhance cationic dye adsorption.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.

Metal doping introduces redoxactive sites that may catalyse dye degradation in addition to adsorption.

“Metal doping introduces redoxactive sites that may catalyse dye degradation in addition to adsorption.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.

Pore filling allows dye molecules to diffuse into mesopores and micropores.

“Pore filling allows dye molecules to diffuse into mesopores and micropores.”

Probably not a substantial claim. The paper’s conclusions may not depend on it.

Co-doping with multiple heteroatoms may create synergistic effects.

“Co-doping with multiple heteroatoms may create synergistic effects.”

Probably not a substantial claim. It may state two separate claims as one.

Converting agricultural wastes into adsorbents provides local solutions for wastewater treatment and reduces reliance on imported materials.

“Converting these wastes into adsorbents provides local solutions for wastewater treatment and reduces reliance on imported materials.”

It may state two separate claims as one.

These interactions can be summarised as universal trends: cationic dyes favour negative and aromatic surfaces, anionic dyes favour protonated or amine-functionalised surfaces, and large aromatic dyes benefit from π-π interactions and pore filling.

“These interactions can be summarised as universal trends: cationic dyes favour negative and aromatic surfaces, anionic dyes favour protonated or amine-functionalised surfaces, and large aromatic dyes benefit from π-π interactions and pore filling.”

It may state two separate claims as one.

Alkaline treatments create hydroxyl groups and increase negative surface charge.

“Alkaline treatments create hydroxyl groups and increase negative surface charge.”

It may state two separate claims as one.

Slow pyrolysis produces more biochar with higher fixed carbon and surface functional groups.

“Slow pyrolysis, with low heating rates (5-10 °C min⁻¹) and long residence times (30-60 minutes), produces more biochar with higher fixed carbon and surface functional groups.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.

For cationic dyes such as methylene blue, crystal violet, basic blue and malachite green, electrostatic attraction occurs between the positively charged dye molecules and negatively charged oxygen-containing groups (e.g., carboxyl, phenolic, carbonyl) on the biochar surface.

“For cationic dyes such as methylene blue, crystal violet, basic blue and malachite green, electrostatic attraction occurs between the positively charged dye molecules and negatively charged oxygen-containing groups (e.g., carboxyl, phenolic, carbonyl) on the biochar surface.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.

Polymer impregnation may block pores and reduce surface area, so a balance is needed.

“However, polymer impregnation may block pores and reduce surface area, so a balance is needed.”

It may state two separate claims as one.

High salt concentration can either interfere with dye molecules by competing for adsorption sites or can shield the charge on the surface of the biochar particles resulting in less adsorption.

“For example, high salt concentration can either interfere with dye molecules by competing for adsorption sites or can shield the charge on the surface of the biochar particles resulting in less adsorption.”

Probably not a substantial claim. The paper’s conclusions may not depend on it.

Fast pyrolysis yields more bio-oil and less biochar.

“Fast pyrolysis, with high heating rates (>100 °C s⁻¹) and short residence times (<2 seconds), yields more bio-oil and less biochar.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.

Moderate pyrolysis temperatures often yield biochar with a balanced combination of surface area and functional groups.

“Moderate pyrolysis temperatures often yield biochar with a balanced combination of surface area and functional groups.”

It may state two separate claims as one.

Heating rate affects pore development: slow heating allows for gradual release of volatiles and formation of micropores, while fast heating favours mesopores.

“Heating rate affects pore development: slow heating allows for gradual release of volatiles and formation of micropores, while fast heating favours mesopores.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.

The effect of temperature on adsorption is seen as it affects both the enthalpy and kinetics of adsorption; i.e. endothermic adsorption is increased at higher temperatures whereas exothermic adsorption can be reduced.

“The effect of temperature on adsorption is seen as it affects both the enthalpy and kinetics of adsorption; i.e. endothermic adsorption is increased at higher temperatures whereas exothermic adsorption can be reduced.”

It may state two separate claims as one.

Phosphorus doping introduces acidic sites that can attract basic dyes and increases hydrophilicity.

“Phosphorus doping introduces acidic sites that can attract basic dyes and increases hydrophilicity.”

Probably not a substantial claim.

The success of biomass-derived biochar in dye removal depends on both sustainability and performance considerations.

“The success of biomass-derived biochar in dye removal therefore depends on both sustainability and performance considerations.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.

Modifications may increase cost and complicate regeneration.

“However, modifications may increase cost and complicate regeneration.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.

Nitrogen-doped and graphitic structures can enhance electron donor-acceptor interactions with dyes.

“Nitrogen-doped and graphitic structures can enhance electron donor-acceptor interactions with dyes.”

It may state two separate claims as one.

Feedstock composition and nitrogen content can also enhance adsorption.

“Feedstock composition and nitrogen content can also enhance adsorption.”

Probably not a substantial claim. The paper’s conclusions may not depend on it.

In batch systems, equilibrium can be reached relatively quickly because mass transfer is not limited by flow.

“In batch systems, equilibrium can be reached relatively quickly because mass transfer is not limited by flow.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.

Lignin-rich feedstocks often yield biochar with higher aromaticity, ash content and stability, whereas cellulose-rich feedstocks may produce biochar with more oxygenated functional groups.

“Lignin-rich feedstocks often yield biochar with higher aromaticity, ash content and stability, whereas cellulose-rich feedstocks may produce biochar with more oxygenated functional groups.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.

Physical modifications such as ball milling, ultrasound and steam explosion can increase surface area, expose internal pores and introduce defects that enhance adsorption.

“Physical modifications such as ball milling, ultrasound and steam explosion can increase surface area, expose internal pores and introduce defects that enhance adsorption.”

Probably not a substantial claim. It may be too vague to check against evidence. The paper’s conclusions may not depend on it. It may state two separate claims as one.

Modifications must be chosen carefully, and metal impregnation may not always be advantageous.

“This shows that modifications must be chosen carefully, and metal impregnation may not always be advantageous.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.

Freundlich constants also provide information on surface heterogeneity and adsorption intensity.

“Freundlich constants also provide information on surface heterogeneity and adsorption intensity.”

It may state two separate claims as one.

The chitosan-bagasse composite also followed pseudo-second-order kinetics and an endothermic process.

“The chitosan-bagasse composite also followed pseudo-second-order kinetics and an endothermic process [6].”

• cites [6] Akl, 2024, Scientific Reports sourceNot checked yet

  Checked before — its earlier verdict is held back until a new check runs.

• AssumptionThe authors state this as an assumption: The pseudo-first-order model implies physisorption with diffusion control, while the pseudo-second-order model implies chemisorption where chemical bonding limits the rate.

It may state two separate claims as one.

Anthraquinone dyes have planar aromatic structures with carbonyl groups that can form hydrogen bonds and π-π interactions with biochar.

“Anthraquinone dyes have planar aromatic structures with carbonyl groups that can form hydrogen bonds and π-π interactions with biochar.”

It may state two separate claims as one.

Sulphur doping can create electron-rich thiophene-like structures that participate in π-π interactions and redox reactions.

“Sulphur doping can create electron-rich thiophene-like structures that participate in π-π interactions and redox reactions.”

Probably not a substantial claim. It may state two separate claims as one.

Feedstock composition varies widely, and there is a need for local characterisation and optimisation.

“However, feedstock composition varies widely, and there is a need for local characterisation and optimisation.”

It may state two separate claims as one.

Acid treatments produce -COOH, -SO3H and -OH groups that donate electrons or form hydrogen bonds.

“Acid treatments produce -COOH, -SO₃H and -OH groups that donate electrons or form hydrogen bonds.”

It may state two separate claims as one.

Triphenylmethane dyes have a bulky, non-planar structure that may prevent them from entering micropores, making mesoporous biochar more suitable for their adsorption.

“Triphenylmethane dyes have a bulky, non-planar structure that may prevent them from entering micropores, making mesoporous biochar more suitable for their adsorption.”

It may state two separate claims as one.

Acidic conditions protonate biochar functional groups and reduce electrostatic repulsion.

“Acidic conditions protonate biochar functional groups and reduce electrostatic repulsion.”

It may state two separate claims as one.

Ionic strength can change the thickness of the electrical double layer surrounding biochar particles which can alter the degree of electrostatic attraction/repulsion between dye molecules and biochar particles.

“Ionic strength can change the thickness of the electrical double layer surrounding biochar particles which can alter the degree of electrostatic attraction/repulsion between dye molecules and biochar particles.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.

Metal impregnation or nanoparticles can introduce redox activity that aids adsorption and catalytic degradation.

“Metal impregnation or nanoparticles can introduce redox activity that aids adsorption and catalytic degradation.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.

Multivalent cationic species (i.e.Ca2+, Mg2+) can bind with dye molecules and thus affect the adsorption of dyes.

“Multivalent cationic species (i.e.Ca2+, Mg2+) can bind with dye molecules and thus affect the adsorption of dyes.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.

Biochar-based magnetic composites will allow for the physical separation of the adsorbed materials.

“biochar-based magnetic composites that will allow for the physical separation of the adsorbed materials.”

Probably not a substantial claim. The paper may give no reason why it holds. It may state two separate claims as one.

The sustainability of biochar as a treatment method will depend on the amount of energy required to produce it, the chemicals used to modify it, and the environmental impacts associated with its production and disposal.

“The sustainability of biochar as a treatment method will depend on the amount of energy required to produce it, the chemicals used to modify it, and the environmental impacts associated with its production and disposal.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.

By integrating datasets on biochar physicochemical properties, dye molecular features and adsorption performance, models such as artificial neural networks, random forests and support-vector machines can predict adsorption capacity and optimise preparation conditions.

“By integrating datasets on biochar physicochemical properties, dye molecular features and adsorption performance, models such as artificial neural networks, random forests and support-vector machines can predict adsorption capacity and optimise preparation conditions.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.

Ultrasonic treatment can clean and open pores.

“Ultrasonic treatment can clean and open pores.”

Probably not a substantial claim. The paper may give no reason why it holds. It may state two separate claims as one.

Successful lab-based trials rarely translate into effective field-based applications due to low regeneration stability, usage of artificial dye solutions, lack of studies performed using continuous flow, and real wastewater streams.

“Successful lab-based trials rarely translate into effective field-based applications due to low regeneration stability, usage of artificial dye solutions, lack of studies performed using continuous flow, and real wastewater streams.”

Probably not a substantial claim. It may be too vague to check against evidence. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.

Combining physical modifications with chemical activation may further improve performance but raises questions about cost and scalability.

“Combining physical modifications with chemical activation may further improve performance but raises questions about cost and scalability.”

Probably not a substantial claim. It may be too vague to check against evidence. The paper’s conclusions may not depend on it.

Their reliability depends strongly on data quality, diversity and transparency.

“However, their reliability depends strongly on data quality, diversity and transparency.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.

Iron oxide modified biochars have been demonstrated to both remove dye pollutants and phosphate from water.

“iron oxide modified biochars that have been demonstrated to both remove dye pollutants and phosphate from water”

It may state two separate claims as one.

When produced under moderate to high temperatures, activated or chemically modified biochars have shown good adsorption capacity for cationic dyes; however, anionic dyes are much harder to remove and require the biochar to be specifically designed to interact with them.

“For example, when produced under moderate to high temperatures, activated or chemically modified biochars have shown good adsorption capacity for cationic dyes; however, anionic dyes are much harder to remove and require the biochar to be specifically designed to interact with them.”

Probably not a substantial claim. It may be too vague to check against evidence. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.

Treatment methods combining adsorption (which includes biochar) with biodegradation or advanced oxidation technologies may potentially provide a wider range of treatment options.

“Treatment methods combining adsorption (which includes biochar) with biodegradation or advanced oxidation technologies may potentially provide a wider range of treatment options.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.

Ball milling reduces particle size, increases external surface area and can induce mechanochemical reactions with additives.

“Ball milling reduces particle size, increases external surface area and can induce mechanochemical reactions with additives.”

It may state two separate claims as one.

Biochar made from biomass is one potential, though still in its infancy, solution for removing textile dyes.

“Biochar made from biomass is one potential, though still in its infancy, solution for removing textile dyes.”

Probably not a substantial claim. It may be too vague to check against evidence. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.

Currently, there is very little mechanistic understanding of the process at the molecular level and needs to be studied using various forms of advanced spectroscopy and modeling.

“Currently, there is very little mechanistic understanding of the process at the molecular level and needs to be studied using various forms of advanced spectroscopy and modeling.”

Probably not a substantial claim. It may be too vague to check against evidence. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.

These approaches can reveal non-intuitive relationships and reduce experimental trial-and-error.

“These approaches can reveal non-intuitive relationships and reduce experimental trial-and-error.”

Probably not a substantial claim. It may state two separate claims as one.

The lack of standardised datasets and the underreporting of negative results increase the risk of overfitting and limit model transferability.

“The lack of standardised datasets and the underreporting of negative results increase the risk of overfitting and limit model transferability.”

Probably not a substantial claim. The paper may give no reason why it holds.

Cost-effectiveness is directly related to the cost of the raw materials, lifespan of the biochar adsorbent, and how efficiently it may be regenerated.

“Cost-effectiveness is directly related to the cost of the raw materials, lifespan of the biochar adsorbent, and how efficiently it may be regenerated.”

Probably not a substantial claim. The paper may give no reason why it holds. It may state two separate claims as one.

The many variables include; feedstock composition, temperature during pyrolysis, functional groups found on the surface, and electronic properties.

“The many variables include; feedstock composition, temperature during pyrolysis, functional groups found on the surface, and electronic properties.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.

Machine-learning and data-driven approaches are emerging as powerful tools for rational biochar design.

“Machine-learning and data-driven approaches are emerging as powerful tools for rational biochar design.”

Probably not a substantial claim.

Biochar's adsorption performance is influenced by much more than just surface area.

“A key review of this subject emphasizes that biochar's adsorption performance is influenced by much more than just surface area.”

Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.

Steam explosion disrupts the lignocellulosic matrix and increases porosity.

“Steam explosion disrupts the lignocellulosic matrix and increases porosity.”

Probably not a substantial claim. The paper may give no reason why it holds.

Real textile wastewater contains metals, pharmaceuticals, nutrients and microplastics in addition to dyes.

“Real textile wastewater contains metals, pharmaceuticals, nutrients and microplastics in addition to dyes.”

Probably not a substantial claim. The paper may give no reason why it holds.

The variability of the feedstocks used to produce biochars along with variable experimental conditions (i.e.different pH's, temperatures etc.) hinders comparisons between studies.

“The variability of the feedstocks used to produce biochars along with variable experimental conditions (i.e.different pH's, temperatures etc.) hinders comparisons between studies.”