The application of the modified durian biomass fiber as adsorbent for effective removal of ammonia nitrogen

In recent decades, water pollution is a great global concern, especially ammonia nitrogen pollutants cannot be ignored due to their toxicity to the surrounding environment. To solve the problem, great attention has been paid to developing novel adsorbent that has the characteristic of efficiency, durability and sustainability. Herein, durian biomass fiber modified with Cu-Al bimetallic oxide (Cu-Al/DBF) with hierarchical structure was successfully synthesized by hydrothermal reaction using natural waste durian shell as the biomass carbon precursor and Cu-Al/DBF was applied in the removal of ammonia nitrogen from wastewater. Different characterizations were employed to determine the morphology, composition and structure of the adsorbent. The prepared biomass-based adsorbent showed outstanding adsorption performance towards ammonia nitrogen pollutants. Maximum adsorption capability of Cu-Al/DBF was fitted out to be 18.04 mg/g from the Langmuir isotherms model. The proposed adsorbent exhibited good reusability that the removal rate of ammonia nitrogen remained above 73% after 5 cycles. In addition, kinetics and thermodynamics were combined to further study the adsorption mechanism. The results showed that the synergistic combination of surface adsorption and chemical adsorption played important role in the removal process. The removal of total ammonia nitrogen in actual domestic sewage (total ammonia nitrogen, TN, 12.6-16.2 mg/L) was investigated. The results indicated that the prepared Cu-Al/DBF has excellent TN adsorption and recycling performance, and the adsorption and stability performance is significantly higher than that of the commercial activated carbon. The interactions between biomass material with large surface area and metal oxide provide great potential for the real application in the water treatment.