Preparation of Sodium Humate-Modified Biochar Absorbents for Water Treatment

Dou, Guolan; Jiang, Zhiwei

doi:10.1021/acsomega.9b02227

Cited by 27 publications

(15 citation statements)

References 41 publications

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“…Figure S12 shows that the biochar can be reused for at least 5 cycles without losing its absorption capacity. 17 The initial mass used was 0.101 g biochar; after five cycles of regeneration, the mass of biochar after regeneration was 0.098 ± 0.001 g, with a relative error of 3.5% compared to the initial mass. Although the mass loss is almost negligible, it may decrease the dye removal after several regenerations.…”

Section: Resultsmentioning

confidence: 96%

“…The adsorption after the regeneration studies was very close to the initial 30% for all the five cycles, reducing only 3% from the initial dye removal after the fifth cycle as shown in Figure S11 (relative error of 10.3% between the initial and the lowest adsorption in the fifth cycle). Figure S12 shows that the biochar can be reused for at least 5 cycles without losing its absorption capacity . The initial mass used was 0.101 g biochar; after five cycles of regeneration, the mass of biochar after regeneration was 0.098 ± 0.001 g, with a relative error of 3.5% compared to the initial mass.…”

Section: Resultsmentioning

confidence: 99%

“…The textile industry is the second largest after agriculture in India, employing over 45 million people directly and 60 million indirectly. 17 It contributes about 14% of the total industrial production of India. This article aims to provide a sustainable solution for the real textile effluent from the house dyers at Coimbatore, Tamil Nadu, India.…”

Section: Introductionmentioning

confidence: 99%

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Effective Removal of Acid Dye in Synthetic and Silk Dyeing Effluent: Isotherm and Kinetic Studies

et al. 2021

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Here, we propose a low-cost, sustainable, and viable adsorbent (pine tree-derived biochar) to remove acid dyes such as acid violet 17 (AV), which is used in the silk dyeing industry. As a case study, the AV removal process was demonstrated using synthetic effluent and further as a proof of concept using real dye effluent produced from the Sirumugai textile unit in India. The pine tree-derived biochar was selected for removal of aqueous AV dye in batch and fixed-bed column studies. The adsorbent material was characterized for crystallinity (XRD), surface area (BET), surface morphology and elemental compositions (SEM–EDX), thermal stability (TGA), weight loss (DGA), and functional groups (FTIR). Batch sorption studies were performed to evaluate (i) adsorption at various pH values (at pH 2 to 7), (ii) isotherms (at 10, 25, and 35 °C) to assess the temperature effect on the sorption efficiency, and (iii) kinetics to reveal the effect of time, adsorbent dose, and initial concentration on the reaction rate. After systematic evaluation, 2 g/L biochar, 25 mg/L AV, pH 3, 40 °C, and 40 and 360 min in a completely mixed batch study resulted in 50 and 90% dye removal, respectively. The isoelectric point at pH 3.7 ± 0.2 results in maximum dye removal, therefore suggesting that monitoring the ratio of different effluent (acid/wash/dye) can improve the colorant removal efficiency. The Langmuir isotherm best fits with the sorption of AV to biochar, provided a maximal dye uptake of 29 mg/g at 40 °C, showing that adsorption was endothermic. Fixed-bed studies were conducted at room temperature with an initial dye concentration of 25 and 50 mg/L. The glass columns were packed with biochar (bed depth 20 cm, pore volume = 14 mL) at an initial pH of 5.0 and a 10 mL/min flow rate for 120 min. Finally, the regeneration of the adsorbent was achieved using desorption studies conducted under the proposed experimental conditions resulted in 90–93% removal of AV even after five cycles of regeneration.

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Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effective Removal of Acid Dye in Synthetic and Silk Dyeing Effluent: Isotherm and Kinetic Studies

et al. 2021

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“…To study the adsorption characteristics and adsorption rates of different biochar, quasi-first-order kinetic, quasi-second-order kinetic, and intra-particle diffusion models were used to analyze them 49 , 50 where q t is the adsorption capacity (mg/g) at time t , k 1 is the quasi-first-order adsorption rate constant (min –1 ), q e is the adsorption capacity at the adsorption equilibrium (mg/g), and k 2 is the quasi-second-order adsorption rate constant [g/(mg·min)].…”

Section: Resultsmentioning

confidence: 99%

Preparation of Acid- and Alkali-Modified Biochar for Removal of Methylene Blue Pigment

Liu

Wang

et al. 2020

ACS Omega

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Walnut shell biochar (WSC) and wood powder biochar (WPC) prepared using the limited oxygen pyrolysis process were used as raw materials, and ZnCl2, KOH, H2SO4, and H3PO4 were used to modify them. The evaluation of the liquid-phase adsorption performance using methylene blue (MB) as a pigment model showed that modified biochar prepared from both biomasses had a mesoporous structure, and the pore size of WSC was larger than that of WPC. However, the alkaline modified was more conducive to the formation of pores in the biomass-modified biochar materials; KOH treatment resulted in the highest modified biochar-specific surface area. The isothermal adsorption of MB by the two biomass pyrolysis charcoals conformed to the Freundlich equation, and the adsorption process conformed to the quasi-second-order kinetic equation, which is mainly physical adsorption. The large number of oxygen-containing functional groups on the particle surface provided more adsorption sites for MB adsorption, which was beneficial to the adsorption reactions. The adsorption effects of woody biomass were obviously higher than that of shell biomass, and the adsorption capacities of the two raw materials’ pyrolysis charcoal were in the order of WPC > WSC. The adsorption effects of different treatment reagents on MB were in the order ZnCl2 > KOH > H3PO4 > H2SO4. The maximum adsorption capacities of the two biomass treatments were 850.9 mg/g for WPC with ZnCl2 treatment and 701.3 mg/g for WSC with KOH treatment.

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“…Since water leaching is not efficient in the removal of organic compounds from biochar, acid or alcohol washing can be a more successful alternative [ 21 ]. Biochar, produced through the pyrolysis of inexpensive agricultural and forest residues, has been widely used as an alternative low-cost adsorbent to treat environmental pollution [ 22 ]. Many different human activities can increase salt pollution in surface water and drinking water resources and considering the growing problem with soil and water salinization, the prospect of biochar application for removal of sodium salts necessitates further and detailed studies.…”

Section: Introductionmentioning

confidence: 99%

Characterization and Sodium Cations Sorption Capacity of Chemically Modified Biochars Produced from Agricultural and Forestry Wastes

et al. 2021

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Excessive amounts of sodium cations (Na+) in water is an important limiting factor to reuse poor quality water in agriculture or industry, and recently, much attention has been paid to developing cost-effective and easily available water desalination technology that is not limited to natural resources. Biochar seems to be a promising solution for reducing high loads of inorganic contaminant from water and soil solution, and due to the high availability of biomass in agriculture and forestry, its production for these purposes may become beneficial. In the present research, wheat straw, sunflower husk, and pine-chip biochars produced at 250, 450 and 550 °C under simple torrefaction/pyrolysis conditions were chemically modified with ethanol or HCl to determine the effect of these activations on Na sorption capacity from aqueous solution. Biochar sorption property measurements, such as specific surface area, cation exchange capacity, content of base cations in exchangeable forms, and structural changes of biochar surface, were performed by FTIR and EPR spectrometry to study the effect of material chemical activation. The sorption capacity of biochars and activated carbons was investigated by performing batch sorption experiments, and adsorption isotherms were tested with Langmuir’s and Freundlich’s models. The results showed that biochar activation had significant effects on the sorption characteristics of Na+, increasing its capacity (even 10-folds) and inducing the mechanism of ion exchange between biochar and saline solution, especially when ethanol activation was applied. The findings of this study show that biochar produced through torrefaction with ethanol activation requires lower energy demand and carbon footprint and, therefore, is a promising method for studying material applications for environmental and industrial purposes.

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Preparation of Sodium Humate-Modified Biochar Absorbents for Water Treatment

Cited by 27 publications

References 41 publications

Effective Removal of Acid Dye in Synthetic and Silk Dyeing Effluent: Isotherm and Kinetic Studies

Effective Removal of Acid Dye in Synthetic and Silk Dyeing Effluent: Isotherm and Kinetic Studies

Preparation of Acid- and Alkali-Modified Biochar for Removal of Methylene Blue Pigment

Characterization and Sodium Cations Sorption Capacity of Chemically Modified Biochars Produced from Agricultural and Forestry Wastes

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