Application of cherry stones for the removal of brilliant green

Abstract

Dyes, which are widely used in many industries, are often discharged into the water, without further treatment, causing serious problems for human health and the natural ecosystems. Brilliant green (BG) is a cationic dye, with genotoxic and carcinogenic properties and therefore needs to be separated from wastewater. In this study, environmental and low-cost food industry waste, cherry stones, was mechanically treated in order to obtain sorbent (CS) and analysed for the sorption of BG. Sorbent CS was characterized by SEM-EDX and ATR-FTIR technique, while the pHsus and pHpzc were also evaluated. Characterization results revealed that CS pose multilayer porous surface, rich in functional groups (dominantly carboxyl and hydroxyl) with pHpzc close to 5, indicating plausible interaction with BG at pH values greater than this one. Sorption experiments were conducted in a stirring batch system under isothermal conditions. The influence of operating parameters such as pH, sorbent contact time and initial dye concentration on the sorption of BG was investigated. The nonlinear forms of two adsorption isotherms (Langmuir and Freundlich) were used to analyze the sorbent uptake capacity. The maximum sorption capacity obtained by Langmuir model was found to be 189.05 mg/g (with adsorbent dosage 2 g/L, in BG concentration range 10 – 200 mg/L, pH = 7, agitation speed 200 rpm and T=25 oC). Results from this study suggest that CS sorbent, as a renewable resource which is, at the same time, waste from the food industry, have a potential to be applied for removing BG dye from contaminated wastewater.