Chemical Approaches to Water and Environmental Remediation: Advanced Materials for the Removal of Emerging Contaminants

Abstract

The increasing occurrence of emerging contaminants in water resources has become an important environmental and chemical challenge. Conventional water-treatment systems were primarily designed to remove pathogens, suspended solids, nutrients, and selected organic and inorganic pollutants, but many newly recognized contaminants can persist or pass through conventional treatment processes. Pharmaceuticals, personal-care products, endocrine-disrupting compounds, pesticides, industrial additives, per- and polyfluoroalkyl substances, antibiotics, and microplastic-associated chemicals represent important groups of emerging contaminants. Their occurrence at low concentrations does not necessarily imply negligible environmental significance because some substances can exhibit biological activity even at trace levels. Advanced chemical approaches based on adsorption, membrane separation, advanced oxidation, photocatalysis, electrochemical treatment, and catalytic degradation provide promising strategies for addressing these pollutants. Advanced materials, including activated carbon, biochar, graphene-based materials, carbon nanotubes, metal and metal-oxide nanoparticles, zeolites, mesoporous materials, metal-organic frameworks, polymeric membranes, and hybrid nanocomposites, can enhance contaminant removal through adsorption, catalytic transformation, or selective separation. This paper examines the chemical principles underlying these technologies, their applications in water remediation, advantages and limitations, and the challenges associated with regeneration, toxicity, secondary pollution, cost, and large-scale implementation. Particular emphasis is placed on developments reported up to 2017. The paper argues that effective remediation requires integration of material science, analytical chemistry, reaction engineering, and environmental risk assessment. Future treatment systems will need to move beyond simple removal toward complete contaminant destruction, resource recovery, safe material reuse, and prevention of secondary environmental impacts.