Preparation and application of Mg-Al composite oxide/coconut shell carbon fiber for effective removal of phosphorus from domestic sewage

A simple and cheap adsorbent using waste coconut shell fiber (CSF) as the biomass carbon precursor was successfully prepared with the in-situ growth of Mg-Al composite oxide and the resulting Mg-Al/CSF with fractional structure was used for the removal of phosphorus from wastewater. The fractional precipitation of Mg-Al composite oxide on the carbon fiber was achieved by simple immersion method and calcination method. The morphology, composition analysis and specific area of the raw and modified CSF was characterized by SEM, XRD and BET. The maximum adsorption capability of Mg-Al/CSF towards phosphorus was fitted out to be 60.39 mg/g from the Langmuir isotherms model with pH 6, temperature 45 degrees C. The phosphorus removal mechanism was verified by the kinetics and thermodynamics results, which was the synergistic combination of surface adsorption and chemical adsorption. In addition, the Mg-Al/CSF adsorbent worked well over the total phosphorus (TP, 0.8-1.1 mg/L) in actual domestic sewage. The results indicated that the prepared Mg-Al/CSF achieved over 50% TP removal in a wide range from 50 to 200 min, which is obviously higher than that of commercial activated carbon. Furthermore, the average TP removal rate of Mg-Al/CSF could reach 46% after recycling for 3 times, which is still much higher than that of commercial activated carbon (28%). The superior recycles results demonstrated the excellent regeneration performance and stability of the prepared sample. The interactions between biomass material with large surface area and metal oxide could be a promising candidate for the other pollutant treatment. (C) 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

The Mg-Al/CSF adsorbent prepared using waste coconut shell fiber demonstrated excellent performance in removing phosphorus from wastewater, showing good regeneration and stability. Compared to commercial activated carbon, it exhibited superior efficiency in phosphorus removal.