Adsorption of methyl violet from aqueous solutions by the biochars derived from crop residues

• Published in: Bioresource technology Vol. 102; no. 22; pp. 10293 - 10298
• Main Authors: Xu, Ren-kou, Xiao, Shuang-cheng, Yuan, Jin-hua, Zhao, An-zhen
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.11.2011; Elsevier
• Subjects: Adsorption; Agronomy. Soil science and plant productions; Applied sciences; Arachis hypogaea; Biochar; Biological and medical sciences; Cations; Charcoal - chemistry; Combustion; Crop residues; Crops; Crops, Agricultural - chemistry; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Gentian Violet - isolation & purification; Hydrogen-Ion Concentration; Ion Exchange; Kinetics; Leaching; Methyl violet; Oryza sativa; Osmolar Concentration; Pollution; Rice; Solutions; Spectroscopy, Fourier Transform Infrared; Straw; Surface chemistry; Temperature; Use of agricultural and forest wastes. Biomass use, bioconversion; Waste Products - analysis; Waste water; Waste water of dye; Wastewaters; Water Pollutants, Chemical - isolation & purification; Water treatment and pollution; Waste water of dye; Adsorption; Biochar; Methyl violet; Crop residues; Carbonization; Dyes; Aqueous solution; Waste water
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2011.08.089

► Biochars from crop residues had great adsorption capacity for methyl violet. ► The adsorption involved electrostatic attraction, specific interaction and surface precipitation. ► Langmuir equation could be used to describe the adsorption of methyl violet by the biochars. The adsorption of methyl violet by the biochars from crop residues was investigated with batch and leaching experiments – adsorption capacity varied with their feedstock in the following order: canola straw char>peanut straw char>soybean straw char>rice hull char. This order was generally consistent with the amount of negative charge of the biochars. Zeta potentials and Fourier transform infrared photoacoustic spectroscopy, combined with adsorption isotherms and effect of ionic strength, indicated that adsorption of methyl violet on biochars involved electrostatic attraction, specific interaction between the dye and carboxylate and phenolic hydroxyl groups on the biochars, and surface precipitation. Leaching experiments showed that 156g of rice hull char almost completely removed methyl violet from 18.2L of water containing 1.0mmol/L of methyl violet. The biochars had high removal efficiency for methyl violet and could be effective adsorbents for removal of methyl violet from wastewater.