Pretreatment of sulfonic acid wastewater through iron-carbon micro-electrolysis: investigation on process optimization and mechanism analysis

λ Fe–C micro-electrolysis was optimized to treat high-strength sulfonic acid wastewater. λ Fe–C micro-electrolysis was optimized for high-strength sulfonic acid wastewater. λ UV–Vis and FTIR identified methylsulfonic and alkylbenzenesulfonic acids. λ The degradation of sulfonic acid wastewater followed a pseudo-second-order kinetic model (R 2  = 0.996). λ Sulfonic acid wastewater degradation followed pseudo-second-order kinetics. λ Economic assessment confirmed feasibility at a cost of 5.0 USD/m 3 .