Fabrication of CMC-PVP based RGO modified magnetic hydrogel for the adsorption and photo-reduction of hexavalent chromium from simulated waste water

Chromium (VI) is considered as highly toxic among other heavy metal ions due to its carcinogenic activity. The present laboratory scale experiment depict the fabrication of CMC/PVP-RGO-NiFe2O4 (CPRN) based hydrogel. The CPRN was investigated for the adsorption and photo reduction removal of hexavalent chromium (Cr VI). Here Carboxymethyl cellulose (CMC) & Polyvinylpyrrolidone (PVP) taken as main backbone for the hydrogel fabrication. The reduced graphene oxide (RGO) was taken as surface modifier followed by nano NiFe2O4 as magnetic substrate. The fabricated magnetic hydrogel composite (CPRN) was characterized by using XRD, FTIR, FESEM, and HR-TEM. The adsorption results showed that about 92.2% of Cr (VI) has been adsorbed on CPRN over a time period of 2 h. On the other hand about 94.7% was photo-reduced over 1 h of solar illumination. The kinetics of overall adsorption and photo-reduction process are pseudo-second-order fits and follow the Langmuir models, which suggests the single layered adsorption mechanism. The maximum adsorption capacity of CPRN was estimated about 338.6 mg/g.