Nanoscale layered double hydroxide modified hybrid nanomaterials for wastewater treatment: A review

Abstract

Wastewater treatment has been a major challenge for scientific society due to complex nature of wastewater and increased demand of clean water supply. In this review, we have critically examined the progress made in development of nanoscale layered double hydroxide (LDH) based hybrid nanomaterials for the treatment of different kind of environmental pollutants present in wastewater. Broad analyses on synthesis of LDH nanomaterials through various routes and their modification by carbon nanotubes, graphene oxides, graphitic carbon nitrides, and magnetic nanomaterials have been given. A survey on characterization tools like XRD, SEM-EDS, TEM, FTIR, XPS, TGA-DTA, and BET surface area are also given. Applications of LDH based hybrid nanomaterials for the cleaning of wastewater containing heavy metals, dyes, antibiotics, phosphates, pharmaceuticals, and other organic compounds have been critically discussed. Role of solution pH, temperature, and co-existing ions as operating parameters were examined and a remediation mechanism towards LDH and pollutants interaction have been drawn. Application of LDH nanomaterials for real wastewater system has been evaluated. An analysis of recycling and regeneration of LDH nanocomposites have been also compiled. Although LDH based hybrid nanomaterials have been used in every spheres of wastewater remediation, yet, there are some major issues like application in multi-pollutant system, remediation of emerging contaminants such as harmful hormones, enhancement of surface area, and inactivation of harmful microorganisms still needs to be solved. Further attention is needed in the low-cost synthesis of LDHs based nanocomposites so it can be easily applied in the real wastewater systems. © 2022 Elsevier B.V.