Enriched phosphate adsorption using lanthanum organic frameworks decorated papaya biochar supported alginate composite

• Novel alginate based papaya biochar coated lanthanum organic frameworks composite was hydrothermally prepared for phosphate removal. • Developed composite was achieved most adsorption capacity within 30 min. • The composite removes phosphate in standard water as well as field water. • The prepared composite is an eco-friendly and regenerable material. The enhance phosphate level (>0.5 mgL −1 ) in water bodies leads to eutrophication. Hence, the current study focuses on alginate based papaya biochar coated lanthanum organic frameworks supported composite namely APBCLOF biopolymer composite was synthesized by the hydrothermal way for the phosphate removal from water. The surface morphology, functional groups and composition of elements in the developed APBCLOF composite were analyzed by SEM, FTIR and EDAX respectively. The factors influencing phosphate adsorption, including solution pH, temperature, contact time and co-ions were carried out under batch level. Within 30 min, the prepared APBCLOF composite reached maximum phosphate adsorption capacity (47.5 mg/g) at neutral pH 7. Freundlich isotherm was proved as more effective than other isotherm models for describing phosphate adsorption. As the temperature increases, the reaction and diffusion rate increase were increased which was illustrated by kinetic studies. The thermodynamic studies confirmed that phosphate adsorption on APBCLOF composite occurred spontaneously. The APBCLOF composite has achieved 70 % phosphate removal efficiency upto 5 cycles. The field study results confirmed the suitability of the developed APBCLOF composite under field conditions.