Synthesis, characterization and application of cinnamoyl C-phenylcalix[4]resorcinarene (CCPCR) for removal of Cr(III) ion from the aquatic environment

In this paper, we report about a synthesis of cinnamoyl C-phenylcalix[4]resorcinarene (CCPCR) and its application as an adsorbent for Cr(III) removal from the aquatic environment. The CCPCR was synthesized by hydrolyzing cinnamoyl C-phenylcalix[4]resorcinaryl octaacetate (CCPCROA) with NaOH. This material than were characterized by using FTIR, BET-BJH and proton-NMR (¹H NMR) spectroscopy methods. Based on characterization data shows that CCPCR has a physics characteristic such as light yellow solid colour, melting point of 390 °C, yield of 61.60% and it has a mesopore structure. The effect of initial concentration, pH and contact time on Cr(III) removal from water samples was investigated by using a batch system. The result shows that the removal of Cr(III) was highest at pH 7, contact time for 45 min and the initial concentration of Cr(III) is 25 mg/L. Kinetic modeling and isotherm modeling were also studied by using 8 and 5 models, respectively. The adsorption kinetics of Cr(III) on CCPCR was followed Pseudo Second Order (PSO) model, while isotherm adsorption of Cr(III) onto CCPCR can be explained well by the Langmuir isotherm model. Overall, the adsorption capacities of Cr(III) on the CCPCR surface is 0.55 mg/g. The desorption or recycling process is going well and eventually reaches 100% by using 55 mL of 1 M HCl. The mechanism of Cr(III) adsorption on the CCPCR surface was followed chemical adsorption via protonation of phenolic-OH or -OR groups on CCPCR.