Fabrication of Pea pods biochar-NH2 (PBN) for the adsorption of toxic Cr6+ ion from aqueous solution

Chromium (Cr) ion is regarded as a particularly hazardous contaminant due to its high toxicity and potential carcinogens. The Cr6+ ions were removed in the current work using a new fabricated low-cost adsorbent called Pea pods biochar-NH2 (PBN). PBN was characterized using BET, BJH, SEM, FTIR, TGA, DSC, XRD, XPS and EDX. The surface area and the pore size of PBN were decreased due to the amination process on the pea pods' biochar-H2O2 (PBO). Optimized condition of different parameters of Cr6+ ions adsorption by PBN was observed at the pH 1.5, contact time (180 min), starting concentration (100 mg/L), and 0.1 g of PBN. The maximal adsorption capacity (Qm) of PBN is 384.62 mg/g. Different error models were used to test the isotherm models' results. The mechanism of the adsorption was proposed based on the XPS analysis. The adsorption process had an R-2 value of 0.999 as the best fit with the Freundlich isotherm (FIM) and pseudo-second-order kinetic (PSOM) models. These obtained data explored that the generated PBN can be a novel, cost-effective material for the adsorption of Cr6+ ions from an aqueous solution.

Automated summary

In this study, a new low-cost adsorbent called Pea pods biochar-NH2 (PBN) was used to remove the highly toxic and potential carcinogen Cr6+ ions. PBN was characterized and optimized conditions for Cr6+ ions adsorption were determined. The experimental results showed that PBN had a maximum adsorption capacity of 384.62 mg/g and fitted well with the Freundlich isotherm and pseudo-second-order kinetic models.