Tailoring Zr-Based MOFs for Tetracycline, Atrazine, and Sulfathiazole from the Aqueous Phase through a Comparative Study of Defect Engineering and Chemical Modifications

Emerging contaminants, including pharmaceutical personal care products and herbicides, pose a threat to water quality and ecosystem health, including human society, as they are not effectively removed by traditional wastewater treatment plants. The complex interactions between the adsorbents and emerging contaminants (ECs) in various aqueous phases are still not yet fully understood, hindering the rational development of the materials for their enhanced and selective removal. This study addresses this challenge by systematically investigating the adsorption mechanisms and kinetics of representative ECs under varying aqueous conditions. We synthesized a water-stable MOF, UiO-66, and modified it by either defect engineering or chemical functionalization to evaluate their performance. Results show that defect-controlled UiO-66 exhibited superior removal efficiency across all tested compounds compared to chemically modified variants, even in the presence of coexisting cations (K+, Na+, Mg2+, and Ca2+) and anions (nitrate and sulfate). Furthermore, the defect-controlled MOF demonstrated stability over three reuse cycles and greater selectivity for hydrophilic ECs relative to activated carbon, a widely used benchmark adsorbent. These findings provide valuable insights into designing sorbents with tunable properties for selective water remediation, thereby advancing solutions to challenges at the water-energy-environment nexus.