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|a Laboratory experiments were designed to identify the adsorption features of Pb2+ by sorghum vinasse (SV) under various conditions. The results showed that the adsorption capacity enhanced with the increasing pH and peaked (68.42 ± 1.42 mg g-1) when pH = 6. With the SV dosage ranging from 0.0250 to 0.2000 g, the adsorption capacity declined from 55.59 to 44.84 mg g-1, and the Pb2+ removal rates increased from 13.52% to 91.14%. The adsorption capacity reached 95.4% of the maximum adsorption capacity at the 10th min, then rose slowly with respect to contact time and equilibrated at the 360th min. When the initial Pb2+ content < 400 mg L-1, the adsorption capacity increased quickly, then it did not vary significantly with the increasing initial Pb2+ concentration. These suggest that the initial pH, adsorbent dosage, contact time, and the initial Pb2+ concentration can significantly affect the adsorption process. The pseudo-second-order kinetic and Langmuir model could well illustrate the adsorption process. The adsorption of Pb2+ on SV is a chemical and spontaneous process via monolayer adsorption involving physical absorption, ion exchange, surface complex with OFGs, and chemical reactions. © 2022, HARD Publishing Company. All rights reserved.
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