Adsorption of Frequently Used Antibiotics From Contaminated Water Using Peanut Shells

Abstract

The removal of pharmaceutical contaminants from water using cost-efficient and environmentally friendly adsorbents has proven to be extremely effective. The adsorption of amoxicillin (AMX) and tetracycline (TET) from wastewater using peanut shells (PS) were described in this study. The PS was characterized using Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray (EDX) techniques. The pH at the point of zero charge (pHpzc) of PS was determined to be 6.5. The influence of operating parameters such as pH, time, initial concentration, adsorbent mass and temperature on the adsorption were evaluated. The adsorption data best fit the Sips isotherm with R2 value of 0.999 for both AMX and TET and the maximum adsorption capacities of PS were obtained to be 42.47 mg g-1 for TET and 61.44 mg g-1 for AMX. Adsorption data were found to fit the pseudo first-order kinetic model for both AMX and TET. Thermodynamic parameters ΔG, ΔH and ΔS were determined to be 3.86, -8.88 and -41.36 for TET adsorption and -2.74, -16.64 and -45.15 for AMX adsorption. The negative ΔH values show that both adsorptions were exothermic while the ΔG values show that the adsorption was spontaneous for AMX and non-spontaneous for TET. The results show peanut shells is effective for the removal of AMX and TET from wastewater.