Efficient phosphorus recovery utilizing Magnesium-Modified Oil-Based drilling cutting Ash: Unraveling the role of ammonia nitrogen independent of struvite formation

Abstract

A novel approach to phosphorus recovery is introduced in this study, employing alkali-melted and magnesium-modified oil-based drill cutting ash (AM-Mg-OBDCA) as highly efficient and cost-effective adsorbents. This innovation represents a notable stride in harnessing the resource potential of oil-based drill cutting ash (OBDCA). An investigation into the impact of ammonia nitrogen on phosphorus recovery was undertaken, revealing enhanced ammonia nitrogen removal in the presence of phosphorus. Simultaneously, the presence of ammonia nitrogen exhibited a favorable influence on phosphorus elimination across a broad pH range and in the co-presence of ions. Particularly under acidic conditions, AM-Mg-OBDCA demonstrated exceptional phosphorus adsorption efficiency. Conversely, co-existing carbonate ions were observed to significantly hinder phosphorus adsorption, while bicarbonate ions exerted only marginal inhibition on ammonia nitrogen adsorption. To discern the adsorption behavior, the pseudo-second-order and Langmuir models were applied, unveiling theoretical adsorption capacities of 161.8 mg/g and 98.81 mg/g for ammonia nitrogen and phosphorus onto AM-Mg-OBDCA, respectively. The forms of phosphorus in the spent AM-Mg-OBDCA were analyzed utilizing the Standard Measurement Test (SMT) phosphorus classification, shedding light on potential mechanisms governing phosphorus and ammonia nitrogen adsorption/co-adsorption. Investigation into the prospective reuse of AM-Mg-OBDCA as a fertilizer subsequent to phosphorus adsorption was conducted, bolstering its environmentally benign potential. In essence, this research introduces an inventive and efficacious strategy for repurposing OBDCA waste into functional materials with valuable applications. By tackling the challenges posed by phosphorus pollution and offering a pathway for resource utilization, this study makes a substantial contribution to the advancement of both environmental preservation and the development of sustainable materials.