Fabrication of New Hyper-cross-linked Polymer for Efficient Heavy Metal Adsorption from Industrial Wastewater

Abstract

Water pollution is the emerging issue in modern world that may cause water scarcity for our future generations. Therefore, it is ultimate need to develop highly efficient and cost-effective methods to solve this issue. Due to this intense demand, a new hyper-cross-linked polymer (HCP) of resorcinol (1, 3-dihydroxybenzol) “R-HCP” is synthesized using Friedel–Craft reaction for the removal of cadmium metal ions from industrial wastewater. Real industrial wastewater samples are used to evaluate the adsorption capability of R-HCP. Fabricated R-HCP is characterized through Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), EDX (energy-dispersive X-ray spectroscopy) and BET (Brunauer–Emmett–Teller). The BET surface area of R-HCP is 221.5848 m²g⁻¹. Through salt addition method, the point of zero charge (PZC) was also determined, and its value is 2.0 pH. The maximum adsorption capacity of R-HCP is 10 mg/g for cadmium metal ions. The greatest adsorption value of 93% was obtained at pH 10 with 0.5 g of adsorbent and 9-min contact time and favors exothermic reaction. Langmuir, Freundlich and Temkin isotherms were studied, and results shows that Freundlich model is the best fit with R² value of 0.9917. Adsorption kinetic investigation shows that it follows pseudo-first-order kinetic model R² value 0.9874. The study of the effect of interfering ions including calcium, magnesium, sodium and potassium demonstrates the decrease in the adsorption capacity to a little extent. R-HCP can be recycled and have regeneration capacity, which is novel and distinguished feature of this adsorbent.