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Removal of lead(II) from aqueous solution using date seed-derived biochar: batch and column studies
- Mahdi, Zainab, Yu, Qiming J., El Hanandeh, Ali
- Applied water science 2018 v.8 no.6 pp. 181
- Fourier transform infrared spectroscopy, adsorbents, adsorption, aqueous solutions, biochar, biomass, calcium chloride, cation exchange, desorption, dose response, hydrochloric acid, lead, models, pH
- This study explored the adsorption of lead ion from aqueous solution onto biochars produced from date seed biomass. Initial evaluation of nine date seed-derived biochars showed that biochar prepared at 550 °C and heating time of 3 h (DSB550-3) was the best adsorbent for Pb²⁺ ion removal. Therefore, it was selected for further investigation in batch and column experiments. The effects of contact time, initial Pb²⁺ concentration, and solution pH were studied. Solution pH showed strong effect on the adsorption ability of DSB550-3 biochar to the lead ion, and the maximum adsorption capacity was found to occur around pH 6.0. The batch maximum adsorption capacity of DSB550-3 biochar was 0.360 mmol g⁻¹. The equilibrium data were adequately fitted to Freundlich and Langmuir isotherms (R² = 0.97). The adsorption kinetics were best described by pseudo-second-order model (R² = 0.94). The breakthrough curve obtained from the column experiment was best described by the modified dose–response model (R² = 0.95). The desorption efficiencies of Pb²⁺ were 2.1%, 23%, 12%, and 55% for DI water, 0.1 M HCl, 0.1 M CaCl₂, and a combination of 0.1 M HCl + 0.1 M CaCl₂ eluents, respectively. FTIR analysis and batch experiments results suggested that Pb²⁺ adsorption mechanism was dominated by complexation with active surface groups, precipitation, and cation exchange. Experimental and model results suggested that date seed-derived biochar has high adsorption capacity for Pb²⁺ compared to other plant-based biochars reported in other literature.