Hydrothermal Fabrication of Zirconium Oxyhydroxide Capped Chitosan/Kaolin Framework for Highly Selective Nitrate and Phosphate Retention

In recent years, hydrothermal technology has been paid more attention because of its unique advantages like large surface area and high porous nature. In the present study, chitosan (CS) embedded kaolin (KN) clay, namely, CSKN composite, was prepared. To enhance the sorption capacity (SC) and selectivity, zirconium oxyhydroxide (ZrO(OH)2) was coated onto CSKN composite to get Zr@CSKN composite using in situ precipitation (In situ) and hydrothermal (Hydro) methods. The developed Zr@CSKN composite was used toward nitrate and phosphate removal, which helps in the minimization of methemoglobinemia (blue baby syndrome) and eutrophication. The adsorbents were characterized using FTIR, XRD, SEM, BET, and EDAX with mapping analysis. Various adsorption influencing factors like contact time, adsorbent dosage, pH, co-anions, initial ion concentration, and temperature were optimized. The experimental data was fitted with various isotherms and thermodynamic parameters to find the nature of adsorption. The reuse and field studies of Zr@CSKN composite were also examined.