Superior adsorptive removal of ciprofloxacin by graphene oxide modified Ni-Al layered double hydroxide composites

Pharmaceutical drug removal from industrial wastewater has become a major challenge in recent years. To address this concern, an eco-friendly, non-toxic, renewable, low-cost, and simple-to-synthesize catalyst called NiAl LDH (Layered Double Hydroxide) was synthesized using the co-precipitation method. LDH was further constructed with GO (Graphene Oxide) using the electro-self-assembly method for its effective performance in the removal of ciprofloxacin from wastewater. XRD, FESEM, EDX, Raman, FTIR, UV-Vis DRS, and BET analysis were used to characterize the as-prepared Ni-Al LDH and composites of GO@LDH. Using bare LDH and its composite with GO, several parameters such as adsorbent dosage, contact time, adsorbate concentration, and pH were optimized. GO(5)@LDH shows complete adsorption of 87.4% in 180 min for ciprofloxacin solution. The SBET for Ni-Al LDH, GO(1)@LDH, and GO(5)@LDH was determined to be in the order 3.5456 m2/g, 19.575 m2/g, and 22.5591 m2/g, suggesting that the surface area of the LDH increases upon GO loading. According to the calculation based on Langmuir isotherm, GO(5)@LDH (1968.5 mg/g) has a greater maximum adsorption capacity than Ni-Al LDH (332.2 mg/g). The kinetic analysis reveals that it adheres to a pseudo-second-order kinetic model. The catalyst was effectively employed for four repeating cycles with only a 10% decrease in removal rate, demonstrating that it can be easily regenerated. The morphology of the catalyst GO(5)@LDH remained the same before and after use, as seen by the XRD spectra, indicating the stability of the catalyst. As a result, LDH-GO composites are ideal catalysts for the treatment of ciprofloxacin wastes in the environment.