A Novel Biosorbent-based Freshwater Acid Treated Carbonized Algal Biomass for Efficient Removal of Hexavalent Chromium
摘要
In this work, algae biomass has been carbonized and chemically treated to prepare Acid@CAB to remove Cr(VI) from the simulated wastewater. The biosorption efficiency of Acid@CAB for Cr(VI) was determined in batch mode experiments. Acid@CAB was characterized using FESEM, EDX, XRD, Zeta potential, and FTIR. Sorption behaviour was investigated using isotherm and kinetic models. The FTIR spectrum showed that Acid@CAB had hydroxyl (-OH), carboxyl (-COOH), and amine (-NH2) functional groups in the process of removing Cr(VI) ions. Acid@CAB exhibited a crystallinity index of 42.41%. The maximum removal of Cr(VI) by Acid@CAB was 89.6% at 80 mg L−1 Cr(VI) concentration, pH 2 with a 0.8 g dose in 30 min. The kinetic correlation coefficients (R2 = 0.985 for 50 mg/L) of the Pseudo-second-order model indicates that the Cr(VI) adsorption onto Acid@CAB was dominated by chemisorption. The low value of the chi-square error analysis also confirmed that the PSO model will be fitted in the sorption process. The Langmuir isotherm revealed that Acid@CAB has the maximum monolayer adsorption of 54.6 mg/g. The thermodynamics tests confirmed that adsorption was favorable, spontaneous and endothermic. In addition, Acid@CAB sequestered 77% Cr(VI) after four ad-desorption cycles, whereas eluent 0.1 M NaOH desorbed 96% from the surface, exhibiting improved recycling capacity. The feasibility and cost-effectiveness studies boost their use as eco-friendly Acid@CAB for Cr(VI) sequestration from aqueous solution.