Water disinfection using moringa protein adsorbed on rice husk ash

Untreated surface water and groundwater are the primary sources of drinking water in many parts of the world, particularly in low-income regions. In these communities, the availability of low-cost water treatment technologies is especially critical in reducing incidences of waterborne diseases. In the present study, we explore the use of Moringa seeds for disinfecting contaminated water. Moringa seeds are known to contain proteins that have antibacterial and coagulant properties; however, the seeds also contain soluble organics that can serve as food for pathogen regrowth, causing storage issues with the treated water. To address this problem, we investigated the adsorption of Moringa proteins (MOP) onto rice husk ash (RHA) and assessed whether the proteins retained their antibacterial properties. The experimental analysis was divided into two parts. The first part evaluated the effect of initial Moringa dosage and contact time on the MOP sorption. The second part investigated the effect of MOP dose, E. coli contamination levels, and contact time on MOP disinfection. Results showed that MOP is bound strongly on the RHA surface and is not released back into solution. Results of the disinfection experiments revealed that the E. coli that adhered onto MOP-functionalized RHA surface were inactivated. Although higher E. coli removal was observed in bare RHA, the adhered E. coli cells on the bare RHA surface remained viable. Overall, these results suggest a potential practical solution to the undesired co-release of soluble organic matter in Moringa seeds.