Main content area

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.