Publication

Abstract : A novel ternary composite hydrogel was fabricated to detoxify Cr(VI) using biopolymer gelatin reinforced with nano lanthanum hydroxide decorated graphene oxide (GLG). Rod-like La(OH)3 nanoparticles were decorated on graphene sheets, and these fillers were uniformly dispersed throughout the gelatin matrix. The resulting mesoporous hydrogel is spherical, with an average diameter of 1.993 mm. The highest adsorption rate is observed at pH 3.5, after a reaction time of 120 min, using 0.4 g GLG2 and 50 mg/L Cr(VI) solution at 298 K. The presence of sulphate ions interfered with the uptake of chromate ions due to similarities in charge, size, and hydration energy. A comprehensive study on the mechanism revealed that the efficient uptake of Cr(VI) is prompted by electrostatic attraction, ion exchange, and partial reduction of Cr(VI) to Cr(III). The ternary system exhibited stable regeneration characteristics for three consecutive cycles. The large-scale applicability of GLG hydrogel was tested using a continuous flow system. The maximum bed capacity was estimated as 21.03 mg/g at 0.5 mL/min flow rate for a total volume of 3.5 L. Furthermore, the proposed hydrogel demonstrated remarkable performance in the adsorption of Cr(VI) from real electroplating effluent.