Hydraulic Properties of Sapwood from Common African Plants and Their Application in Drinking Water Filtration:A Low-Cost, Sustainable Water Purifification Solution for Rural Africa

Abstract

Rural areas  in Africa face a severe shortage of clean drinking water, and traditional water  purification  methods  are  difficult  to  popularize  d ue  to  issues  such  as  cost, energy consumption, and sustainability. This study aims to explore the use of sapwood from common native African plants as a low-cost, biodegradable, and easily accessible natural filtration material to address local drinking water safety issues. We selected the common African gymnosperm  Gnetum africanum and cycad species (Encephalartos spp.),  as  well  as  the   angiosperm   Moringa  o leifera,  to  systematically  study  the anatomical structure  and  hydraulic  properties  of their sapwood. Scanning  electron microscopy (SEM) was used to observe the microscopic structure of the xylem and the morphology  of  pit  membranes.  A  pressure-driven  filtration  setup  and  hydraulic conductance measurement system were used to quantitatively analyze the sapwood's water  conductivity,  pore  size  distribution,  and  filtration  efficiency  for typical water contaminants such as  E. coli. The results show that although the xylem structures of the three plants differ, they all exhibit effective bacterial filtration capabilities. Among them, Moringa oleifera sapwood demonstrated the best overall performance due to its unique  wide  vessels  and  simple  perforation  plates,  exhibiting  high  water  fl ux  and efficient  bacterial  retention. The sapwood of  Gnetum africanum and  Encephalartos spp.  also  showed   potential  for  application   under  specific  conditions,   but  their hydraulic efficiency was relatively low. This study successfully constructed a prototype of a  low-cost,  high-efficiency water filtration  device  based  on  plant  sapwood. This research provides a new scientific basis and a feasible technical path for developing localized,  sustainable  water  purification  technologies  suitable  for  resource-limited areas in Africa. It is expected to significantly improve the drinking water safety of local residents, reduce the transmission risk of waterborne diseases, and holds significant public health importance and application value.