Adsorptive removal of Remazol Brilliant Blue R dye from its aqueous solution by activated charcoal of Thuja orientalis leaves: an eco-friendly approach

Anthraquinone dyes are one of the major water pollutants due to their stability and persistence in the aquatic system. The present study describes the use of activated charcoal prepared from Thuja orientalis leaves (ACTOL) as an adsorbent to remove reactive anthraquinone dye Remazol Brilliant Blue R (RBBR) from its aqueous solution. In this work, leaves of the plant were carbonated to get fine charcoal which was activated by acid treatment and analysed by BET, SEM and FTIR techniques. Batch experiments were conducted to study the effect of pH, contact time, concentration and amount of adsorbent on the removal of RBBR in the concentration range 0.1–6.65 m mol L −1 . The highest efficiency was found to be 81% at pH 6 and contact time of 300 min. Adsorption data were analysed by Langmuir, Freundlich and Temkin isotherm models. The adsorption was found to follow Freundlich adsorption isotherm ( R 2 = 0.9972). The kinetic study of the process was done by analysing the time adsorption data with pseudo-first-order, pseudo-second-order and intraparticle diffusion models, and it was found to obey pseudo-second-order kinetics. The adsorbent showed 73% of efficiency even after four regeneration cycles. FTIR analysis revealed that the various groups present at the surface of adsorbent were responsible for uptake of dye molecules. This study reveals that leaves of Thuja orientalis, a common biowaste, can be used as an efficient adsorbent for the removal of RBBR dye from its aqueous solution. It provides an economical and eco-friendly way to mitigate the waste and use it as an adsorbent.