Enhanced adsorption of ceftriaxone and cefotaxime using ZnAl ‐ LDH and graphene‐modified ZnAl ‐ LDH in wastewater treatment

Antibiotics are frequently detected in trace amounts in pharmaceutical and hospital effluents, presenting significant risks to human health and aquatic ecosystems. Layered double hydroxides (LDHs) and their hybrids are gaining attention as affordable and efficient adsorbents for water treatment; herein, we investigate the eradication of two antibiotics, ceftriaxone (CFT) and cefotaxime (CFX), using calcined ZnAl‐LDH (LDH‐C) and a graphene‐loaded calcined ZnAl‐LDH (G‐LDH‐C) composite as an adsorbent. Microscopy analysis confirmed the uniform dispersion of graphene nanosheets over the LDH surface, while analysis (TGA) demonstrated the thermal stability of the synthesized adsorbent. Adsorption was optimized by varying pH, temperature, adsorbent dosage, contact time, and initial concentration. The G‐LDH‐C showed maximum capacities of 54.34 mg/g for CFT and 45 mg/g for CFX at pH 5 with a 10 mg/L dosage, reaching equilibrium at 60 and 45 min, respectively. Isothermal studies showed that CFT and CFX adsorption followed a monolayer and homogeneous process consistent with the Langmuir model. Kinetic analysis revealed that CFX fits well with the PFO model, while CFT aligned better with the PSO model. Thermodynamic results indicated that adsorption of both antibiotics was exothermic and spontaneous. Recyclability study showed that after seven cycles, there is a gradual decrease in adsorption capacity. CFT (G‐LDH‐C) adsorption capacity decreased from 26.5 to 15.4 mg/g, while CFT (LDH‐C) declined from 23.9 to 10.2 mg/g. Similarly, CFX (G‐LDH‐C) decreased from 44.9 to 22.7 mg/g, and CFX (LDH‐C) dropped from 37.9 to 16.3 mg/g, showing good potential as promising candidates for removing antibiotics from wastewater.