Removal of lead(II) from aqueous solution using date seed-derived biochar: batch and column studies

Abstract

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 Pb 2+ ion removal. Therefore, it was selected for further investigation in batch and column experiments. The effects of contact time, initial Pb 2+ 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 (R 2 = 0.97). The adsorption kinetics were best described by pseudo-second-order model (R 2 = 0.94). The breakthrough curve obtained from the column experiment was best described by the modified dose-response model (R 2 = 0.95). The desorption efficiencies of Pb 2+ were 2.1%, 23%, 12%, and 55% for DI water, 0.1 M HCl, 0.1 M CaCl 2 , and a combination of 0.1 M HCl + 0.1 M CaCl 2 eluents, respectively. FTIR analysis and batch experiments results suggested that Pb 2+ 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 Pb 2+ compared to other plant-based biochars reported in other literature.

Removal of selected metal ions using powder of seeds of Ajwaa dates from aqueous solution

“…Experimental and model results by some researchers suggested that date seed-derived bio char has high adsorption capacity for Pb[II] compared to other plant-based biochars. 28 There is paucity of data as well as research on the use of date seed powders as adsorbents for heavy metals. Most research had concentrated on the use of date stones instead of powders as potential adsorbents.…”

Removal of Lead from Water Solution by Reusable Magnetic Adsorbent Incorporating Selective Lead-Binding Peptide

“…Compared to the first adsorption capacity (33.4 mg/g bead), the regenerated capacity in the sixth cycle (31.8 mg/g bead) decreased by less than 5%. By optimizing the desorbing process to regenerate the used adsorbent, as has been previously demonstrated by using various chemicals [30,32], the regeneration efficiency of the constructed peptide bead may improve further. For the reusable gelatin-bentonite adsorbent, 0.1 N nitric acid restored the lead-adsorption capacity to more than 92% of initial capacity after ten adsorption-desorption cycles [32].…”

“…For the reusable gelatin-bentonite adsorbent, 0.1 N nitric acid restored the lead-adsorption capacity to more than 92% of initial capacity after ten adsorption-desorption cycles [32]. For the biochar-based adsorbent used for lead removal, a combination of 0.1 M HCl + 0.1 M CaCl 2 was the best desorbing eluent [30]. The activated carbon is a commonly reported adsorbent for lead removal, and HCl has been shown to be an efficient chemical for desorbing lead from the used adsorbent.…”

“…2020, 10, x FOR PEER REVIEW 5 of 11 increase in lead adsorption was not significant after 1 h, so the time for each of the following adsorption experiments was determined to be 1 h, if not specifically mentioned otherwise. Previous research has shown that the experimental pH can affect the adsorptive uptake of lead ion [29][30][31]. For example, lead can precipitate at pH values equal to or greater than 7, due to the formation of Pb(OH)2 in the solution.…”

“…eluent [30]. The activated carbon is a commonly reported adsorbent for lead removal, and HCl has been shown to be an efficient chemical for desorbing lead from the used adsorbent.…”