Zinc remediation of aqueous solutions by natural hemp fibers: batch desorption/regeneration study

AbstractA hemp waste material resulting from the textile industry has previously been shown to be a very efficient material in removing Zn(II) from diluted aqueous solutions. In this work, batch studies on desorption and multiple sorption–regeneration cycles for zinc(II) removal by natural hemp fibers have been carried out. The best desorption results were performed in acidic medium, where the protons in solution replaced the Zn(II) ions on the loaded hemp. The efficiency of Zn(II) desorption with 0.1 M hydrochloric acid is higher than that achieved using sulfuric acid of the same concentration. The amount of Zn(II) desorbed by 0.1 M HCl, 0.1 M H2SO4, and 5% NaCl increases sharply in the first 15–20 min of the process, attaining values that subsequently stay almost constant (for 0.1 M HCl) or sligtly increase (for 0.1 M H2SO4 and 5% NaCl). The sorptive potential of the tested hemp remains almost unchanged after three cycles of sorption–desorption of Zn(II) from solutions with a high mg Zn/g of hemp in the...