Adsorção de corantes ácidos tricrômicos utilizando óxido de grafeno reduzido obtido de resíduos sólidos de algodão

Abstract

The textile industry faces important challenges related to the generation of liquid waste, mainly due to the treatment applied to effluents generated from the dyeing process using dyes. These inputs have high solubility in water and chemical stability, which makes them difficult to remove using conventional treatment methods. In this context, this work presents an ecological approach in the adsorption of a combination of trichromic acid dyes with the adsorbent reduced graphene oxide (rGO) obtained from cellulosic biomass (rGO-BIO) of cotton fiber waste. The rGO-BIO was characterized by different techniques including HRTEM, Raman, XRD, FTIR, BET and Zeta Potential analysis, which confirmed its structural and chemical properties developed for the adsorption process. The study investigated the impact of variables such as pH, contact time, temperature, adsorbent mass and adsorbent concentration on the performance of the adsorption process. The analyses were performed under a wide range of conditions: solution concentrations from 20 to 200 mg/L, pH ranging from 1 to 12, adsorbent mass from 50 to 200 mg, contact times between 0 and 200 minutes and temperatures from 20 at 60°C. The kinetic model that best suited the reaction was the pseudo-second order with R2 greater than 0.997 and K2 = 0.148 (g/mg min). At the end of the processes, it was established that the ideal parameters for this adsorption were: solution concentrations 50 mg/L, pH 1.5, adsorbent mass of 200 mg, contact times 120 minutes, achieving an initial removal of 97%. in the first 20 min of reaction, to reach equilibrium, stirring speed of 200 rpm, and temperatures of 20 °C. The effective removal of trichrome of acid dyes from synthetic effluents demonstrates the promising potential of this adsorbent derived from industrial cotton waste, presenting itself as an ecologically more sustainable alternative in relation to the synthesis of other materials used to remove this type of contaminant.