Super-efficient removal of yellow 161 anionic dye from water by activated carbon based on coffee grounds

The study evaluates the effectiveness of activated carbon derived from coffee grounds (ACcg) in removing Reactive Yellow 161, a pollutant from the textile industry. The properties of ACcg are analyzed by various techniques such as FTIR, SEM, EDS and X-ray diffraction. In addition, physico-chemical analyses, such as moisture content, ash content, volatile matter, iodine value and zero charge point (pHpzc), were carried out on the prepared ACcg. The Box-Behnken Design (BBD) scheme combined with the Response Surface Method (RSM) is used to optimize adsorption variables. Results show high microporosity of ACcg, adsorption kinetics fitted to pseudo-first order and Langmuir isotherm consistent with experimental data. Thermodynamic parameters indicate spontaneous and exothermic adsorption behavior. Residue analysis and ANOVA confirm a high adsorption capacity of ACcg (97.67 %) at an initial concentration of 20 ppm Reactive Yellow, with an ACcg mass of 1 g/L and a pH of 3. The chosen model is validated for this application.