Removal of CI Basic Yellow 2 from aqueous solution by low-cost adsorbent: hardened paste of Portland cement

The adsorption of C.I. Basic Yellow 2 (BY2) from aqueous solutions on to hardened paste of Portland cement (HPPC) as a low-cost adsorbent and its adsorption kinetics at different conditions were studied. The adsorption process was followed by an online spectrophotometric analysis system, which consisted of a UV-Vis spectrophotometer, a designed spectrophotometric cell, a peristaltic pump and a glass reactor. The effect of experimental parameters, including initial dye concentration, mass of HPPC, initial pH and temperature, on adsorption was studied over a 30 min adsorption period. For the kinetic study, the obtained data were treated according to various kinetic models. The results revealed that the experimental data were better fitted to the first-order kinetics model than to the second-order and intraparticle diffusion models. Equilibrium isotherms for the adsorption of BY2 on HPPC were analysed by Freundlich and Langmuir isotherms equations using the linear correlation coefficient. The Freundlich isotherm gave the best correlation of adsorption.