Development of a low-cost water treatment technology using <italic>Moringa oleifera</italic> seeds

Abstract

The persistent poor access to safe drinking water in low-income regions necessitates the development of low-cost alternatives to available yet expensive water treatment technologies. To address this need, this research investigates the development of a biofilter using the seeds of Moringa oleifera (MO), an indigenous tree in many low-income countries. The protein extracts from the MO seeds have been previously used as a disinfectant and coagulant in water treatment. However, the extraction of the protein leaves behind undesired organics that cause problems in water storage. To eliminate these organics, we immobilized the MO protein extracts onto three adsorbents (sand, commercial activated carbon, and burnt rice husk), and then tested the use of the MO-functionalized adsorbents in E. coli disinfection. The sorption and disinfection studies were carried out using batch equilibrium tests. We implemented a multi-level factorial design to investigate the factors affecting the adsorption and disinfection processes. Results show that the MO protein binds strongly to all adsorbents, and that bound proteins are not released back into the solution. The MO adsorption capacity was highest in activated carbon and lowest in sand. The functionalized adsorbents were able to deactivate E. coli with the highest coliform removal observed in rice husk and activated carbon. Results of one-way ANOVA indicate that the type of adsorbent material is an important factor in E. coli disinfection using MO functionalized adsorbents. However, there is no sufficient evidence to conclude that activated carbon is superior to rice husk. Overall, these results suggest the possibility of designing a low-cost biofilter that uses MO immobilized adsorbents as packing material.

Moringa-functionalized rice husk ash adsorbent for the removal of amoxicillin in aqueous solution

“…Although the presented evidence is not sufficient for a concrete explanation, we hypothesize that a similar sequestration mechanism described in literature is displayed in these results [22][23][24][25]28], have revealed that the chemical structure of MOP suggests that the tail of this protein does not display any coagulation capabilities. This tail may have been the part of the MOP that attached to the surface of RHA and allowed MOP to be immobilized.…”

“…MO protein saturation on the surface of RHA was achieved by soaking RHA in known concentrations of MO solutions (400-1700 mg/L). Sorption equilibrium was observed by reading initial and final equilibrium concentrations of MO proteins in solution at 280 nm [25].…”

“…In the present work, we test the extent to which functionalization of RHA by Moringaoleifera proteins (MOP) can effectively enhance the adsorptive capacity of bare RHA. We have previously presented that moringa-functionalization can be an effective way to enhance the adsorptive capability of RHA to various contaminants in water [22][23][24][25]. We also apply this methodology to assess the extent of amoxicillin removal using the moringa-functionalized RHA.…”