<![CDATA[The discharge of laundry wastewater containing surfactants and phosphates represents a growing environmental concern, particularly in areas where wastewater is released without adequate treatment. This study evaluates sulfuric acid–activated rice husk ash (RHA) as a low-cost adsorbent for removing surfactants and phosphates from real laundry wastewater. FTIR and XRD analyses indicated that the main silica-related functional groups and framework of RHA were largely retained after acid activation, while SEM observations suggested a rougher and more heterogeneous surface morphology. Batch adsorption experiments using real laundry wastewater showed that surfactant and phosphate removal were influenced by adsorbent dosage and contact time. The optimum dosage was 3 g for surfactant removal and 4 g for phosphate removal, while the optimum contact time for both contaminants was 30 min. Controlled isotherm experiments using separate single-solute surfactant and phosphate standard solutions indicated that the adsorption behavior of both contaminants was better described by the Freundlich model, suggesting adsorption on heterogeneous surface sites. Kinetic analysis using real laundry wastewater showed rapid uptake, with the Elovich model providing the best overall fit for both surfactant and phosphate adsorption. These findings suggest that sulfuric acid–activated RHA is a promising, simple, and affordable biomass-derived adsorbent for laundry wastewater treatment, although further studies involving surface area analysis, regeneration, reusability, column operation, and cost performance are required to support practical application.]]>
