Removal of Multi-Class Antibiotic Drugs from Wastewater Using Water-Soluble Protein of Moringa stenopetala Seeds

Abstract

The removal of ten selected antibiotic drugs belonging to different classes (sulphonamides, fluoroquinolones, macrolides, and tetracycline) was investigated using water-soluble proteins from the seeds of Moringa stenopetala. The surface functional groups of water-soluble protein powder before and after removal of antibiotics were characterized using Fourier transform infrared (FTIR). Processing parameters that could affect the removal efficiency, such as initial analyte concentration, protein dosage, and pH were studied. An optimized method was applied to a real wastewater sample collected from Daspoort Wastewater Treatment Plant (WWTP) located in Pretoria, South Africa. Under optimal conditions, the results indicated good agreement between the efficiency of water-soluble proteins to remove antibiotics from the real wastewater sample and from the synthetic wastewater sample prepared in the laboratory using standard solutions with known concentrations. The percentage of removal under optimum conditions (protein dosage of 40 mg, initial analyte concentration of 0.1 mg L−1, and pH 7) was between 85.2 ± 0.01% and 96.3 ± 0.03% for standard mixture solution and from 72.4 ± 0.32% to 92.5 ± 0.84% and 70.4 ± 0.82% to 91.5 ± 0.71% for the real wastewater (effluent and influent) sample.