Solid phase extraction and removal of brilliant green dye on zinc oxide nanoparticles loaded on activated carbon: New kinetic model and thermodynamic evaluation

The brilliant green (BG) solid phase extraction of carried out following accumulation on including zinc oxide nanoparticles loaded on activated carbon (ZNO-NP-AC) non-toxic and green as material. The influence of variables such as pH, initial BG concentration, contact time, amount of adsorbent, eluent and temperature on BG removal and recoveries were studied and optimized. The high correlation coefficient and possibility of accurate prediction and explanation of experimental data by novel kinetic model show its applicability and superiority for representation of experimental data. The results of present model compared with traditional kinetic models (pseudo-first and second order and intraparticle diffusion model). Additionally, fitting the experimental equilibrium data to numerous conventional isotherm models show that the Langmuir model with high correlation coefficient and low error analysis is more usable to explain the experimental data. The calculated change in entropy and enthalpy of BG adsorption on proposed adsorbent was 136.59 J mol−1 K−1 for 15.0 mg L−1 and 65.2 J mol−1 K−1 35.2 kJ/mol and 16.1 kJ/mol for 15 mg L−1. The quantitative elution of retained BG by 2.0 mL of EtOH make permit accurate and repeatable monitoring off BG over wide linear range (0.2–500 ng mL−1) with limits of detection (LODs) of 0.08 ng mL−1. The preconcentration factors were 75 and loading half time (t1/2) values were less than 5 min.