Single-step pyrolysis of biomass waste-derived activated carbon encapsulated zero-valent nickel NPs for the purification of antibiotic-contaminated water†
Abstract
In this study, zero-valent nickel NPs immobilized on biowaste-based activated carbon (ZVNi@AC) were prepared using a single-step pyrolytic reduction/activation method. ZVNi@AC was characterized using various techniques, including BET, SEM, TEM, EDS, FTIR, XRD and point of zero charge (pHpzc) analysis. The nanocomposite is composed of highly porous activated carbon and decorated with ZVNi NPs, with a surface area of 975 m2 g−1. The modified activated carbon (ZVNi@AC) demonstrated a superior adsorption performance (367.59 mg g−1) for cephalexin antibiotic removal compared to the unmodified activated carbon (287.91 mg g−1). Cephalexin adsorption onto ZVNi@AC was most effective at pH 4.5 and 40 °C, where more than 95% of cephalexin was removed within 36 min. Thermodynamic analysis revealed the adsorption process to be spontaneous (negative ΔG°) and endothermic (positive ΔH°). The excellent removal efficiency, reaching up to 92%, of ZVNi@AC for five cycles demonstrated the potential application of this adsorbent for antibiotic removal from wastewater.