Potassium phosphate/magnesium oxide modified biochars: Interfacial chemical behaviours and Pb binding performance

Miao, Qiuci; Li, Guanghe

doi:10.1016/j.scitotenv.2020.143452

Cited by 39 publications

(11 citation statements)

References 56 publications

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“…For a higher production temperature, Pb(II) elimination improved in biochar because of precipitation formed as hydrocerussite and lead oxide phosphate. Wheat straw biochar (WBC) was functionalized via phosphate/magnesium through the pre-treatment of biomass and post-treatment of biochar, noted as WBC_PMA and WBC_PMB, correspondingly (Miao and Li 2021). Since the pyrolysis process enhanced the loading capacity of phosphate/magnesium, WBC_PMA contained additional surface functional groups than WBC_PMB.…”

Section: Heavy Metal Ionsmentioning

confidence: 99%

Biochar for the removal of contaminants from soil and water: a review

Qiu

Liu

Ling

et al. 2022

Biochar

358

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Biochar shows significant potential to serve as a globally applicable material to remediate water and soil owing to the extensive availability of feedstocks and conducive physio-chemical surface characteristics. This review aims to highlight biochar production technologies, characteristics of biochar, and the latest advancements in immobilizing and eliminating heavy metal ions and organic pollutants in soil and water. Pyrolysis temperature, heat transfer rate, residence time, and type of feedstock are critical influential parameters. Biochar’s efficacy in managing contaminants relies on the pore size distribution, surface groups, and ion-exchange capacity. The molecular composition and physical architecture of biochar may be crucial when practically applied to water and soil. In general, biochar produced at relatively high pyrolysis temperatures can effectively manage organic pollutants via increasing surface area, hydrophobicity and microporosity. Biochar generated at lower temperatures is deemed to be more suitable for removing polar organic and inorganic pollutants through oxygen-containing functional groups, precipitation and electrostatic attraction. This review also presents the existing obstacles and future research direction related to biochar-based materials in immobilizing organic contaminants and heavy metal ions in effluents and soil. Graphical Abstract

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Section: Heavy Metal Ionsmentioning

confidence: 99%

Biochar for the removal of contaminants from soil and water: a review

Qiu

Liu

Ling

et al. 2022

Biochar

358

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“…For Cd(II) removal by M-PAAC, the contribution percentages of complexation and precipitation mechanisms were 33.60 and 40.41%, respectively. Among the four main mechanisms, Cd(II) adsorbed by ion exchange was easily desorbed from activated carbon, resulting in secondary pollution . The contribution of ion exchange decreased from 31.37 to 21.50% after modification, indicating that the adsorption of Cd(II) by M-PAAC was more stable.…”

Section: Resultsmentioning

confidence: 99%

“…Among the four main mechanisms, Cd(II) adsorbed by ion exchange was easily desorbed from activated carbon, resulting in secondary pollution. 60 The contribution of ion exchange decreased from 31.37 to 21.50% after modification, indicating that the adsorption of Cd(II) by M-PAAC was more stable. The recovery performance of activated carbon determines its application potential in the environment.…”

Section: Resultsmentioning

confidence: 99%

Contributions of Various Cd(II) Adsorption Mechanisms by Phragmites australis-Activated Carbon Modified with Mannitol

et al. 2022

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Due to its high toxicity, persistence, and bioaccumulation in the food chain, controlling cadmium (Cd) pollution in wastewater is urgent. Activated carbon is a popular material for removing Cd. To improve the Cd(II) adsorption efficiency by increasing the number of oxygen-containing functional groups, Phragmites australis -activated carbon (PAAC) was modified with mannitol at a low temperature (150 °C). The textural and chemical characteristics of PAAC and modified PAAC (M-PAAC) were analyzed by surface area analysis, elemental analysis, Boehm’s titration, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy. Batch adsorption experiments were conducted to investigate the influence of Cd(II) concentration, contact time, ionic strength, and pH on Cd(II) adsorption. The main adsorption mechanisms of Cd(II) on activated carbon were quantitatively calculated. The results showed that mannitol modification slightly decreased the S BET (5.30% of PAAC) and increased the content of carboxyl, lactone, and phenolic groups (total increase of 43.96% with PAAC), which enhanced the adsorption capacity of PAAC by 58.59%. The adsorption isotherms of PAAC and M-PAAC were described well using the Temkin model, while the intraparticle diffusion model fitted the Cd(II) adsorption kinetics best. Precipitation with minerals was a crucial factor for Cd(II) adsorption on activated carbon (50.40% for PAAC and 40.41% for M-PAAC). Meanwhile, the Cd(II) adsorption by M-PAAC was also dominated by complexation with oxygen-containing functional groups (33.60%). This research provides a method for recovering wetland plant biomass to prepare activated carbon and efficiently treat Cd-containing wastewater.

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“…The pseudo-first-order model can be related to physical sorption and the pseudo second-order model assumes that the removal process is controlled by the chemical sorption, which involves the valence forces where the adsorbent and the adsorbate exchange or share electrons [12]. The pseudo second-order model has been reported to better simulate phosphates sorption for biochar from a rice straw/eggshell mixture [12], straw [6], and rosmarinus officinalis [7] pyrolyzed at different temperatures.…”

Section: Effect Of Contact Time On Sorption Processmentioning

confidence: 99%

“…The cost of sorbent production is also one significant parameter for the sustainability of the process. Sorption processes have been examined during the last years in order to remove nutrients from water using natural zeolite, calcite, sand and iron products [5], and biochar or modified biochar [6,7].…”

Section: Introductionmentioning

confidence: 99%

Screening of Raw and Modified Biochars from Food Processing Wastes for the Removal of Phosphates, Nitrates, and Ammonia from Water

2022

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The aim of this work was to compare the performance of biochar from various food processing wastes of different origin for the removal of different nutrients from water. Eggshells (EGS), rice husk (RH), and coffee biochars were pyrolyzed at 400 and 800 °C and were examined for the removal of phosphates, nitrates, and ammonia nitrogen. The raw materials were also modified with magnesium chloride in order to investigate their sorption behavior. The highest sorption capacity (qmax) for phosphates and ammonium was observed with EGS pyrolyzed at 800 °C and was 11.45 mg PO43−-P/g and 11.59 mg NH3-N/g, while the highest nitrates sorption capacity was observed with the magnesium-modified RH pyrolyzed at 800 °C (5.24 mg NO3−-N). The modified EGS biochars pyrolyzed at 800 °C had almost the half the sorption capacity for phosphates and nitrates compared to the unmodified materials. The modification of RH pyrolyzed at 800 °C resulted in higher sorption capacity by 34 and 158% for phosphates and ammonium, respectively. The coffee raw and modified biochars were less efficient in nutrient removal compared to the other materials. The specific surface area values of the biochars examined is not a decisive factor for nutrient sorption. The reaction between magnesium and calcium (for the eggshell samples) ions with phosphates is responsible for the higher sorption efficiency. On the other hand, the presence of magnesium and calcium ions has a detrimental effect on the sorption of NH3-N.

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Potassium phosphate/magnesium oxide modified biochars: Interfacial chemical behaviours and Pb binding performance

Cited by 39 publications

References 56 publications

Biochar for the removal of contaminants from soil and water: a review

Biochar for the removal of contaminants from soil and water: a review

Contributions of Various Cd(II) Adsorption Mechanisms by Phragmites australis-Activated Carbon Modified with Mannitol

Screening of Raw and Modified Biochars from Food Processing Wastes for the Removal of Phosphates, Nitrates, and Ammonia from Water

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