Review on Recent Progress in Wastewater Treatments via Using Alginate-Based Gels as Adsorbent Materials

Wastewater constitutes a significant threat to human and environmental well-being owing to its high concentration of toxic compounds. The existence of heavy metal ions and organic pollutants in wastewater to an acceptable standard level is crucial. Adsorption, an economical, easily implementable, and eco-friendly method, is widely employed to eliminate targeted contaminants from wastewater. A wide array of adsorbent materials has been utilized throughout history, and novel functional materials continue to be developed. Biopolymers, characterized by their chemical structure, cost-effectiveness, environmental compatibility, biocompatibility, and biodegradability, have found applications in adsorption studies. Among these, alginate stands out due to its ability to form gels in the presence of divalent cations, facilitating the entrapment and removal of contaminants. Alginate, a biocompatible and biodegradable polysaccharide, is particularly utilized in adsorption processes due to its chemical properties. Alginate-based materials can form hydrogels, which provide a large surface area for adsorption and enhance the removal efficiency of heavy metals and organic pollutants. In addition to these advantages, alginate hydrogels may have low mechanical strength and, in some cases, may show undesirable dissolution tendencies. A variety of methodologies can be employed to eliminate weaknesses. This review delves into the use of alginate matrix gels for the removal of pollutants in wastewater, featuring an array of relevant studies. Moreover, a concise overview of the adsorption process, kinetics, and isotherms is provided.