A new tool for disinfecting household drinking water for rural residents: protonated mordenite-embedded sheet

Soichiro Hirai,Naoto Matsue,Verónica Américo António Fernando,Satoshi Mitsunobu,Salma Sadia,Erni Johan

doi:10.2166/washdev.2022.202

Soichiro Hirai, Naoto Matsue + Show 4 more

Open Access

https://doi.org/10.2166/washdev.2022.202

Copy DOI

Abstract

Abstract Many rural residents in developing countries drink water contaminated with feces due to inadequate purification, causing many diarrheal deaths, most of them infants. We have fabricated a protonated (H+-retaining) mordenite-embedded non-woven fabric sheet (H-MES) as a new tool for disinfecting drinking water at home. Proton retention amount was 1.2 mmol per gram of mordenite, 75% of its cation-exchange capacity. The H-MES released protons through cation exchange with cations in aqueous solutions, lowering the pH of the solutions to below 4. This low pH led to disinfecting 100 mL of 100-fold diluted TSB solutions containing an Escherichia coli species (DH5α). For example, an initial viable count of around 5,000 CFU mL−1 decreased to 14 CFU mL−1 after 24 h shaking at 25 °C with added H-MES containing 0.2 g protonated mordenite; 3.8×107 CFU mL−1 without the H-MES. Adding a nitric acid solution showed a similar effect, but using chemical reagents at home might lead to unexpected accidents. Adding and removing the H-MES to and from household waterpots by hand is easy. Besides the H-MES, similar sheets embedded with bactericides and bacterial adsorbents could be a simple water-disinfection tool for rural residents.

Highlights

Safe water is essential for people to wash their hands, cook, and drink, but it is not readily available in rural areas of developing countries
The H-MES used for the disinfection experiments retained 1.20 mmol of Hþ per gram of mordenite, with 75% of the cation-exchange sites retaining Hþ
Disinfection property of H-MES Shaking the test solution with a DH5α viable count of around 5,000 CFU mLÀ1 at 25 °C, without adding H-MES, increased the viable count over time: 1.0Â105 CFU mLÀ1 after 6 h; 3.8Â107 CFU mLÀ1 after 24 h (Figure 3(a), the blank run)

Summary

Introduction

Safe water is essential for people to wash their hands, cook, and drink, but it is not readily available in rural areas of developing countries. The World Health Organization (WHO) reported that at least two billion people drink fecal-contaminated water containing pathogens, associated with 485,000 diarrheal deaths each year, most of them infants (WHO 2019). Many rural residents disinfect drinking water through flocculation, filtration, solar disinfection with and without titanium oxide, chlorination, and boiling (Pooi & Ng 2018; Bailey et al 2021; Marobhe & Sabai 2021) These methods work if used properly, but the grave health hazards noted in the above-mentioned WHO report indicate that some residents are not using or are improperly using the methods. Besides the current methods, there is a need for simple and cost-effective methods acceptable to rural residents

Objectives

Methods

Results

Discussion

Conclusion