Kinetics and isotherm studies for the adsorption of Cu(II) from aqueous solution by carbonbased matrix formed using para-nitroacetanilide

Pollution of water is a pragmatic problem in the world today. Contamination by heavy metals and dyes is a major concern of water pollution. This study examines a new adsorbent made by the reaction between para-nitroacetanilide and concentrated sulfuric acid and is the first-ever study carried out to the best of our knowledge. The adsorption of Cu²⁺ has been studied on this adsorbent as a preliminary study. The prepared material was characterized using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), X-ray Fluorescence Spectroscopy (XRF), Powder X-ray Diffraction (PXRD) and point of zero charges (pzc) analysis. The average pore diameter obtained from SEM analysis was 2 μm, concluding that the adsorbent has a desirable morphology for better adsorption. The adsorption experiments were carried out as a function of pH, shaking time, initial Cu²⁺ concentration, and adsorbent dosage. The adsorption kinetics at low concentrations (34.50 mg L^-1 = 1.5 10^-7 mol m^-3) follows pseudo-second-order kinetics with an R² value of 0.99, suggesting a chemisorption process. The adsorption data agree with the Freundlich isotherm at higher concentrations (varying from 17.21 mg L^-1 (7 10^-8 mol m^-3) to 96.25 mg L^-1 (3.6 10^-7 mol m^-3) revealing multilayer adsorption, amounting to a maximum adsorption capacity of 8.31 mg g^-1 at 25⁰C.