Defect, Pore, and Surface Engineering of Nanomaterials for Wastewater Treatment: A Review

Nanomaterials offer high specific surface area and tunable surface chemistry. They can be used as promising adsorbents, photocatalysts, and membrane components for wastewater treatment. However, problems of low efficiency and low recyclability limit the practical application of some nanomaterials. This review summarizes their use for inorganic and organic pollutant removal and examines defects. The modification and controllable construction of nanomaterials in terms of defect regulation, pore structure modification, and surface modification are also summarized. Pore and surface engineering strategies are discussed through a structure–property–performance framework. Then, improvements in pore and surface structures are investigated in relation to the controllable construction of nanomaterials. The evidence indicates that performance gains must be evaluated alongside regeneration, active-material leaching, transformation products, and energy demand. Future progress depends on reproducible comparisons, realistic wastewater testing, and recovery-by-design rather than removal efficiency alone.