Environmental-friendly algal-mediated magnetic activated carbon for adsorptive removal of contaminants from water

•Synthesis of high-yield AC using algae chlamydomonas sp.•Magnetic nanocomposite IAC examined for its removal efficiency for Cr(VI) and DFS.•IAC resulted in 95.2 and 82.1% removal efficiency for Cr(VI) and DFS in 4 h.•5 cycles of regeneration exhibited only 6.6% reduction in removal efficiency by IAC. The presence and persistence of hazardous contaminants including heavy metals and pharmaceutical compound in water have become a matter of great concern worldwide due to their negative impacts on the natural ecosystem and human health. Very few studies have been reported to check the efficiency of a nanosorbent for simultaneous removal of both the contaminants i.e., heavy metals and pharmaceutical compounds. Here, we have attempted to achieve removal of Cr(VI) and DFS by developing a suitable adsorbent. In this study, iron oxide/activated carbon (IAC) magnetic nanocomposite was used as a nanosorbent for decontamination of chromium (VI) and diclofenac sodium (DFS) from aqueous solution over a certain range of experimental parameters. Activated carbon was synthesized using green microalgae Chlamydomonas sp., while to make a sustainable novel nanosorbent, iron oxide nanorods were embedded in the matrix of activated carbon. The composition and structure of nanosorbents were characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EXD) spectroscopy, Brunner-Emmett-Teller (BET), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The batch adsorption studies were conducted from the removal of Cr(VI) and DFS from water by IAC sorbent. The maximum adsorption efficiency of 95.2 and 82.1% for Cr(VI) and DFS, respectively were achieved in less than 4 h for initial concentrations of 10 mgL−1. The adsorption of Cr(VI) and DFS was much higher at acidic pH than at alkaline range. The equilibrium data for Cr(VI) ions adsorption was fitted well with pseudo-second order kinetics, Langmuir isotherm model, Elovich and intraparticle diffusion model. 5 cycles of regeneration and reuse showed that sorption capacity individually decreased by 6.6 and 8.2% for Cr(VI) and DFS, respectively as compared to the original adsorption. Also, excellent magnetic properties enabled via application of iron oxide nanorods significantly ease the separation and regeneration of spent magnetic adsorbents. [Display omitted]