Novel graphene oxide/aminated lignin aerogels for enhanced adsorption of malachite green in wastewater

Biomass adsorbents applied in the removal of pollutants in wastewater treatment has become a trend. Herein, only 0.1 % graphene oxide was used to modify the aminated lignin aerogels and applied in the removal of dyes. The adsorption capacity of graphene oxide/aminated lignin aerogels (GALA) to malachite green (MG) was compared with different composition, pH, aerogels dosage, reaction temperature and contacting time. The experimental results indicated that the maximum adsorption capacity and efficiency could reach to 113.5 mg/g and 91.72 % under the optimal conditions. Compared to other aerogels in this experiment, the adsorption performance of GALA was significantly improved due to the synergy between the carboxyl group on the surface of graphene oxide and the amine of aminated lignin. Additionally, the fitting results of adsorption isotherm models and adsorption kinetic models conformed to the Langmuir and pseudo-second-order models, respectively. Furthermore, the adsorption efficiency of the GALA was able to keep 89.8 % within 5 cycles of adsorption-desorption. Overall, the GALA reduces costs and reuses waste lignin, which were eco-friendly, regenerate and convenient biomass adsorbents that has the good potential for wastewater treatment.