Removal of azo dyes from synthetic wastewater using biochar derived from sewage sludge to prevent groundwater contamination

Textile industries are regarded as one of the major sources of water pollution. The dyeing process consumes a lot of water and emits a lot of wastewater into the environment. This wastewater not only pollutes surface water, but it also pollutes ground water. The adsorption behavior of Acidic Blue 210 (AB210) and Acidic Blue 7 (AB7) azo dyes was examined through a batch adsorption study using activated sewage sludge biochar adsorbent. The sewage sludge material was converted into activated biochar form using chemical synthesis, and activation process and its surface area was obtained using BET surface area analysis. The optimum adsorption parameters were found in batch studies, and the process of adsorption was evaluated by isotherm and kinetic studies. The kinetic studies concluded that pseudo second order kinetic model found to be good fit with R2 value was always >0.96. To nature of azo dye uptake (Exothermic/Endothermic) was obtained in thermodynamic studies, and the observed pollutant material was disposed of by the safe landfilling method. Around 99.32% of AB210 & 94.28% of AB7 azo dyes were removed from the synthetic solutions in this study. [Display omitted] •Chemically activated Sewage sludge derived biochar was used in the investigation•Removal efficiency of 99.32% and 94.28% was obtained for Acidic Blue 210 and Acidic Blue 7.•Adsorption isotherm studies and Kinetic Studies were performed.•Thermodynamic study concluded with negative value of ΔG°, positive value of ∆H° and positive value of ΔS°.