Removal and enrichment of Cr(VI) from aqueous solutions by lotus seed pods

Chromium (Cr(VI)) is highly toxic and carcinogenic. Cr(VI) water pollution has become more and more serious. This article reports on a study in which lotus seed pods (LSP), an agricultural waste product, was used to efficiently remove Cr(VI) from an aqueous solution, and the carbonization product of LSP after the removal of Cr(VI) (CPLSP) can be regarded as a resource containing Cr. Cr(VI) removed by LSP fits a pseudo-second-order model. pH levels greatly influence the amount of Cr removed. The maximum removal of Cr(VI) by LSP in aqueous solution was 153.85 mg/g. The possible removal mechanism is absorption, redox, and reabsorption based upon SEM/EDS, FT-IR, and XPS spectra results. The Cr content of CPLSP was 42.95% by ammonium persulfate oxidation titrimetric method. These results suggest that LSP can be an excellent, low cost, biomaterial for removing and enriching Cr(VI) from an aqueous solution. (c) 2019 Water Environment Federation