Removal of Cr (III) Ions from Wastewater using Sawdust and Rice Husk Biochar Pyrolyzed at Low Temperature

Sorption capacity of two different biochar (saw dust and rice straw) was evaluated in the recovery of chromium from wastewater. The optimum pH was 5-7 for recovery of Cr(III). Optimum yield was received after 1 hour contacting time with an adsorbent dose of 1 g/L and initial concentration was ∼20 mg/L. Cr(III) ions were transported to biochar surface through adsorption and intra-particle diffusion process. Langmuir and Freundlich kinetic parameters indicated that the affinity of the sorbent towards the uptake of Cr(III) ions and adsorptions were favorable. According to FTIR analysis of Cr(III) ions bound to active sites either electrostatic attraction or complexation mechanism. These results indicated that carbonyl, hydroxyl, amine and halides are the main adsorption sites in saw dust and rice straw biochar and these functional groups complexes with Cr(III) ions in the aqueous solution and changed the chemical environment of the functional groups in the biochar.

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Rice Straw Biochar and Magnetic Rice Straw Biochar for Safranin O Adsorption from Aqueous Solution

Water ◽

10.3390/w14020186 ◽

2022 ◽

Vol 14 (2) ◽

pp. 186

Author(s):

Do Thi My Phuong ◽

Nguyen Xuan Loc

Keyword(s):

Aqueous Solution ◽

Adsorption Capacity ◽

Rice Straw ◽

Batch Adsorption ◽

Particle Diffusion ◽

Order Kinetic ◽

Magnetic Biochar ◽

Intra Particle Diffusion ◽

Rice Straw Biochar ◽

Safranin O

This study investigates the adsorption of Safranin O (SO) from aqueous solution by both biochar and magnetic biochar derived from rice straw. Rice straw biochar (RSB) was made by pyrolysis in a furnace at 500 °C, using a heating rate of 10 °C·min−1 for 2 h in an oxygen-limited environment, whilst the magnetic rice straw biochar (MRSB) was produced via the chemical precipitation of Fe2+ and Fe3+. The physicochemical properties of the synthesized biochars were characterized using SEM, SEM- EDX, XRD, FTIR techniques, and N2 adsorption (77 K) and pHpzc measurements. Batch adsorption experiments were used to explore the effect of pH, biochar dosage, kinetics, and isotherms on the adsorption of SO. Experimental data of RSB and MRSB fit well into both Langmuir and Freundlich isotherm models, and were also well-explained by the Lagergren pseudo-second-order kinetic model. The maximum SO adsorption capacity of MRSB was found to be 41.59 mg/g, while for RSB the figure was 31.06 mg/g. The intra-particle diffusion model indicated that the intra-particle diffusion may not be the only rate-limiting step. The collective physical and chemical forces account for the adsorption mechanism of SO molecules by both RSB and MRSB adsorbents. The obtained results demonstrated that the magnetic biochar can partially enhance the SO adsorption capacity of its precursor biochar and also be easily separated from the solution by using an external magnet.

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Desulfurization performance of MgO/ rice straw biochar adsorbent prepared by co-precipitation/calcination route

BioResources ◽

10.15376/biores.15.3.4738-4752 ◽

2020 ◽

Vol 15 (3) ◽

pp. 4738-4752

Author(s):

Jiali Chen ◽

Lianhan Huang ◽

Liming Sun ◽

Xiaofan Zhu

Keyword(s):

Adsorption Capacity ◽

Calcination Temperature ◽

Rice Straw ◽

Active Sites ◽

Weight Ratio ◽

Preparation Conditions ◽

So2 Adsorption ◽

Chloride Hexahydrate ◽

Rice Straw Biochar ◽

Co Precipitation

A solid adsorbent for SO2 adsorption was prepared from magnesium salt/rice straw via co-precipitation/calcination. The effects of various preparation conditions, including the calcination temperature, the weight ratio of Mg/rice straw, magnesium salts, and amine precipitants, were investigated relative to their effects on the desulfurization performance of adsorbents. Maximum sulfur adsorption capacity (260 mg/g) was obtained with MgO/rice straw biochar adsorbent using tetraethylenepentamine (TEPA) as the precipitants, and the preparation conditions included a calcination temperature of 400 °C, a Mg/rice straw weight ratio of 1.2, and magnesium chloride hexahydrate (MgCl2·6H2O) as the magnesium source. The rice straw biochar-supported MgO sample displayed a high SO2 adsorption capacity due to its excellent textural properties, large specific surface areas, small crystallite size, numerous surface active sites of MgO nanoparticles, and introduced N-H groups. The physical and chemical properties of samples were investigated by field emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller (BET) analyses, Fourier transform infrared spectrometer (FT-IR), elemental analysis (EA), and X-ray diffraction (XRD).

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Enhanced fluoride removal from drinking water in wide pH range using La/Fe/Al oxides loaded rice straw biochar

Water Science & Technology Water Supply ◽

10.2166/ws.2021.232 ◽

2021 ◽

Author(s):

Nan Zhou ◽

Xiangxin Guo ◽

Changqing Ye ◽

Ling Yan ◽

Weishi Gu ◽

...

Keyword(s):

Drinking Water ◽

Rice Straw ◽

Fluoride Concentration ◽

Fluoride Removal ◽

Batch Adsorption ◽

Solution Ph ◽

Adsorption Sites ◽

Wide Ph Range ◽

Rice Straw Biochar ◽

Ph Range

Abstract A novel and highly efficient adsorbent was prepared by loading La/Fe/Al oxides onto rice straw biochar (RSBC) and was tested for the ability to remove fluoride from drinking water. Characterized by SEM, XRD, Zetapotential and FTIR, it was found that the ternary metal oxides were successfully loaded on the surface of biochar in amorphous form, resulting in the formation of hydroxyl active adsorption sites and positive charges, which played a synergistic role in fluoride removal. Through batch adsorption tests, key factors including contact time, initial fluoride concentration, initial pH and co-existing anions effects were investigated. Results showed that the tri-metallic modified biochar (La/Fe/Al-RSBC) had excellent fluoride removal performance with an adsorption capacity of 111.11 mg/g. Solution pH had little impacts on the removal of fluoride, the adsorbent retained excellent fluoride removal capacity in a wide pH range of 3.0–11.0. The co-existing anions had almost no effect on the fluoride removal by La/Fe/Al-RSBC. In addition, La/Fe/Al-RSBC could be regenerated and reused. Electrostatic adsorption and ion exchange were responsible for this adsorption behavior. These findings suggested the broad application prospect of a prepared biochar adsorbent based on rare earth and aluminum impregnation for the fluoride removal from drinking water.

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Characterization of Biochars Derived from Different Organic Wastes

Journal of Experimental Agriculture International ◽

10.9734/jeai/2020/v42i430498 ◽

2020 ◽

pp. 44-50

Author(s):

Md. Shahin Hossin ◽

Morsheda Akter Mukta ◽

Md. Abdur Rouf Talukder ◽

Md. Mustafizur Rahman ◽

Md. Sagirul Islam Majumder ◽

...

Keyword(s):

Rice Straw ◽

Rice Husk ◽

Soil Amendment ◽

Chemical Properties ◽

Organic Wastes ◽

Physical And Chemical Properties ◽

Saw Dust ◽

Rice Straw Biochar ◽

Physical And Chemical ◽

And Chemical Properties

Biochar is widely recognized as an efficient tool for soil fertility and carbon sequestration. The understanding of its physical and chemical properties is strongly related to the type of used material, is crucial to identify the most suitable application of biochar in soil. A selection of organic wastes (e.g., rice straw, rice husk and saw dust) with different characteristics were pyrolyzed at 350 0C in order to optimize the physical and chemical properties of biochar as a soil amendment. Bulk density of biochar samples in this study varied from 0.18 mg/m3 to 0.22 mg/m3. Moisture content was in the order of saw dust (8.41%) > rice straw (7.21%) > rice husk (6.74%). Rice straw biochar had highest pH (8.80) and electrical conductivity, EC (3.45 ds/m). The organic carbon was highest in rice straw biochar (46.50%) followed by with rice husk (39.3%) and saw dust (25.3%). The total nitrogen contents of the rice straw, rice husk and saw dust were 1.78%, 1.59% and 1.11%, respectively. The rice straw biochar contents higher available P, as compared to rice husk and saw dust biochar. The rice straw biochar had higher exchangeable Ca (5.60 meq/100 g), Mg (1.70 meq/100 g). This study suggested that the rice straw biochar has a great potential as soil amendment among the three biochars for sustainable soil management.

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Adsorption characteristics of modified rice straw biochar for Zn and in-situ remediation of Zn contaminated soil

Environmental Technology & Innovation ◽

10.1016/j.eti.2021.101388 ◽

2021 ◽

Vol 22 ◽

pp. 101388

Author(s):

Shichao Liu ◽

Zhonglei Xie ◽

Yintao Zhu ◽

Yanmiao Zhu ◽

Yan Jiang ◽

...

Keyword(s):

Rice Straw ◽

Contaminated Soil ◽

In Situ Remediation ◽

Adsorption Characteristics ◽

Rice Straw Biochar

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Morphological and Elemental Investigations on Co–Fe–B–O Thin Films Deposited by Pulsed Laser Deposition for Alkaline Water Oxidation: Charge Exchange Efficiency as the Prevailing Factor in Comparison with the Adsorption Process

Catalysis Letters ◽

10.1007/s10562-021-03642-4 ◽

2021 ◽

Author(s):

Y. Popat ◽

M. Orlandi ◽

S. Gupta ◽

N. Bazzanella ◽

S. Pillai ◽

...

Keyword(s):

Pulsed Laser Deposition ◽

Water Oxidation ◽

Active Sites ◽

High Surface ◽

Pulsed Laser ◽

Industrial Applications ◽

Active Species ◽

Laser Deposition ◽

Core Shell ◽

Adsorption Sites

Abstract Mixed transition-metals oxide electrocatalysts have shown huge potential for electrochemical water oxidation due to their earth abundance, low cost and excellent electrocatalytic activity. Here we present Co–Fe–B–O coatings as oxygen evolution catalyst synthesized by Pulsed Laser Deposition (PLD) which provided flexibility to investigate the effect of morphology and structural transformation on the catalytic activity. As an unusual behaviour, nanomorphology of 3D-urchin-like particles assembled with crystallized CoFe2O4 nanowires, acquiring high surface area, displayed inferior performance as compared to core–shell particles with partially crystalline shell containing boron. The best electrochemical activity towards water oxidation in alkaline medium with an overpotential of 315 mV at 10 mA/cm2 along with a Tafel slope of 31.5 mV/dec was recorded with core–shell particle morphology. Systematic comparison with control samples highlighted the role of all the elements, with Co being the active element, boron prevents the complete oxidation of Co to form Co3+ active species (CoOOH), while Fe assists in reducing Co3+ to Co2+ so that these species are regenerated in the successive cycles. Thorough observation of results also indicates that the activity of the active sites play a dominating role in determining the performance of the electrocatalyst over the number of adsorption sites. The synthesized Co–Fe–B–O coatings displayed good stability and recyclability thereby showcasing potential for industrial applications. Graphic Abstract

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