Removal of natural organic matter fractions by adsorptive asymmetric ceramic membrane functionalized with in situ phytogenic nanoscale zero valent iron: Performance and Fenton cleaning strategy

Extant literature has demonstrated that conventional water treatment processes especially in developing countries struggle in completely removing detrimental organic loads. Emerging research delineates nanomaterials such as nanoscale zero valent iron (nZVI) to have excellent performance in organic matter removal from aqueous media. In this work, nZVI particles were prepared from the liquor of commercially available green tea and supported on kaolin (K-nZVI) and investigated as an adsorbent for natural organic matter (NOM) sequestration from aquatic media. Further, the asymmetric ceramic membrane was prepared by incorporating the developed adsorbent on a concrete support for the removal of NOM. A Fenton cleaning strategy was developed to mitigate fouling. The Brunauer-Emmett-Teller (BET) results revealed the developed adsorbent surface area was greater compared to raw kaolin (27.07 and 11.64 m(3) g(-1), respectively). The scanning electron microscopy (SEM) imagery of the developed adsorbent showed the particle staking was presented as paper slices of varying sizes, an indication of dispersed particles with characteristic plate-like fragments. The synthesized membrane exhibited a pH(ZPC) value of 4.79 +/- 0.03. This meant at pH above 4.79 +/- 0.03, the membrane would be negatively charged, and conversely at pH below the pH(ZPC) value. Membrane fouling due to bovine serum albumin (BSA) deposition showed a 50% flux decline in the first 60 min, coinciding with the rapid adsorption capacity within the same time frame. The optimal cleaning parameters of pH (4.5) and H2O2 (5 mM) gave the best flux recovery rates. This work demonstrated an efficient Fenton cleaning strategy to regenerate the developed membrane.

Automated summary

This study utilized nanoscale zero valent iron (nZVI) and kaolin to prepare an adsorbent for the removal of natural organic matter (NOM) from water. An asymmetric ceramic membrane was developed for the removal of NOM, and a Fenton cleaning strategy was used to mitigate fouling. The results showed that the developed adsorbent had a larger surface area and the synthesized membrane had good flux recovery rates.