Functionalized Modified Polysaccharides as an Excellent Material for the Ni (II) Removal from Heavy Metal Wastewater

The adsorption method for removing heavy metals from landfill leachate has received wider attention due to its simplicity and high removal efficiency. However, it is essential to develop adsorbents with a high adsorption capacity and eco-friendly characteristics. In this study, sodium alginate (SA) was employed as the source material and cross-linked with urea through Glutaraldehyde (GA) to form the new adsorbent SA-urea⁰. The Ni (II) adsorption mechanism and adsorption capacity of SA-urea⁰ adsorbent were explored by static and dynamic experiments. The results indicated that the chemical adsorption was the main adsorption type of new adsorbent SA-urea⁰, involving a chelating reaction between Ni (II) and -NH₂, and a coordination reaction between Ni (II) and -COO⁻. The maximum removal percentage of Ni (II) was 71% at pH 7 with an adsorbent dose of 0.1 g, and it decreased by 23% with the presence of 5 mg/L Cu²⁺. The maximum adsorption capacity of SA-urea⁰ reached 35.75 mg/g in dynamic experiments, and the Yoon-Nelson model was more suitable to describe the dynamic adsorption process. Overall, this study presented a novel adsorbent with enhanced efficiency and practicality for Ni (II) removal, thereby contributing to the advancement of adsorption methods in heavy metal wastewater treatment.