Versatility of p-Imidazolemethylcalix[4]arene-attached silica resin for the removal of lead and cadmium ions from wastewater

Abstract

ABSTRACT Water pollution is a global concern due to the unregulated discharge of various pollutants into aquatic environments without proper treatment. A prominent contributor to environmental degradation and adverse health effects is the unmitigated discharge of heavy metal ions within industrial effluents. The present study revealed the synthesis of p-imidazolemethylcalix[4]arene-based resin (4) and its application as an adsorbent for the removal of toxic metals, i.e., Pb2+and Cd2+, from aqueous media. The synthesis of resin (4) proceeded through well-known organic synthetic procedures and was characterised by different analytical techniques, i.e., FT-IR, SEM and elemental analyses. However, the adsorption process monitored by using UV-Vis spectrophotometer. The adsorption behaviour of resin (4) was evaluated through batch experiments, and different parameters, such as pH, adsorbent dosage and contact time, were optimised. The experimental results were evaluated by the Langmuir and Freundlich isotherm models. Moreover, kinetic and thermodynamic studies were also performed to evaluate the data. The maximum adsorption of toxic metals, 98% and 96%, respectively, for Pb2+and Cd2+ was observed at pH 7 with 30 mg of resin (4) after 1 h at ambient temperature. The results were also compared with those of other reported materials, and it could be concluded that resin (4) has great potential for minimising the risk of environmental water pollution. This novel resin demonstrates exceptional versatility in its capacity to effectively capture a wide range of heavy metal ions present in wastewater, thereby offering a comprehensive solution to a pressing environmental concern. The specific molecular structure of p-Imidazolemethylcalix[4]arene enables selective and efficient adsorption of heavy metal ions, surpassing conventional methods in terms of both effectiveness and versatility. The synthesis and characterisation of this unique resin, coupled with its demonstrated efficacy in heavy metal ion removal, represent a significant advancement in the field of environmental remediation.