Sustainable pectin-derived hydrogels as efficient adsorbents for adsorptive removal of environmental contaminants: A review

The rising pollution of water resources with organic and inorganic pollutants has promoted the use of sustainable, efficient, and biodegradable materials to overcome these issues. The use of pectin, a widely available biopolymer extracted from plant sources, has emerged as a potential route to develop highly absorbent and eco-compatible hydrogel materials with high adsorption capacity. This review provides a detailed account of the major developments and applications of pectin-based sustainable hydrogels to remove environmental contaminants. The chemical structure of pectin, its natural sources, and the pectin extraction technique, particularly the role of molecular properties such as degree of esterification and functional groups in determining adsorption performance. The major properties of pectin hydrogels, like methods of synthesis, cross-linking processes, swelling properties, and physicochemical properties of pectin hydrogels, are critically examined to establish correlations between structure and functionality. This paper systematically reviews recent works on the adsorption capacities of organic contaminants such as dyes and pharmaceuticals, as well as inorganic pollutants like heavy metal ions. The regenerability of pectin-based hydrogels is assessed to evaluate their practical feasibility. The review also compares pectin-based hydrogels with existing adsorbents to demonstrate the competitive ability and potential applications of pectin-based materials. Moreover, the paper highlights challenges associated with the mechanical stability, scalability, and capacity of pectin-based hydrogels when exposed to real wastewater environments, and future research directions are conducted to guide the rational design and development of next-generation pectin-based hydrogel materials for efficient water remediation. • Pectin hydrogels as green adsorbents • Fabrication mechanisms and swelling behaviour • Efficient removal of organic pollutants • Effective remediation of toxic inorganic ions • Reusability, performance, and future challenges