Iron-coated nutshell waste bioadsorbents: Synthesis, phosphate remediation, and subsequent fertilizer application

Environ Res. 2023 Oct 21:117468. doi: 10.1016/j.envres.2023.117468. Online ahead of print.ABSTRACTThe increasing incidence of freshwater nutrient pollution worldwide has highlighted the need for improved phosphate capture technologies. Successful phosphate recovery from agricultural sources and commercial wastewater can help prevent freshwater algal bloom contamination, while also reducing the dependency on finite phosphate reserves. Biodegradable biosorbents have the potential to remove phosphate from water; however, their potential as slow-release fertilizers has not been tested. Novel biosorbents were developed by coating pistachio and walnut shells with iron oxides; batch and column experiments were conducted to investigate their adsorption capacities and performances. Surface characterization studies were also conducted to investigate changes in the surface area and morphology. The potential of using iron-coated shells loaded with phosphorus as slow-release fertilizers was also evaluated. Advanced characterization techniques (scanning electron microscopy, Brunauer-Emmett-Teller (BET) physisorption analysis, and x-ray diffraction) showed that hematite was successfully coated onto the surface, resulting in increased surface area and roughness. The iron-coated pistachio and walnut shell phosphate removal capacity was 12.63 mg g-1 and 9.25 mg g-1, respectively. The phosphate sorption data fitted well with the Freundlich isotherm model and pseudo-second-order kinetics. Inner ...
Source: Environmental Research - Category: Environmental Health Authors: Source Type: research