Permeability, Strength and Filtration Performance for Uncoated and Titania-Coated Clay Wastewater Filters

Abstract

Problem statement: Wastewater problems continue to be a relevant issue, particularly in urban areas. One promising low-cost material for manufacturing porous ceramics as water filter is clay. Clays can be blended with other materials such as polymers to obtain functional ceramic materials. Approach: Ceramic wastewater filters were fabricated from clay using both sol-gel and simple mixing methods followed by hot-pressing and calcination. Polyethylene Glycol (PEG) was used as a poreforming agent. Results: Varying the clay:PEG ratio modified the membrane permeability between 1.65×10 −16 m 2 and 3.16×10 −15 m 2 for the sol-gel membranes and between 1.38×10 −16 and 8.72×10−13 m 2 for membranes prepared by simple mixing. The strength ranged from 0.28 MPa-1.71 MPa for the sol-gel membranes and from 0.05-0.90 MPa for samples prepared by simple mixing. The filtration performance was tested using aqueous solutions of Methylene Blue (MB). The concentrations of MB remaining in the solution varied from 0.98-1.44% for sol-gel filters and from 1.50-38.05% for filters prepared by simple mixing. Conclusion: We succeeded in making ceramic as filter from clay. The porous ceramic can be used to reducing concentration of pollutant simulated. The model introduced has succeeded to explain the experimental observations with percolation approximation.

Titania Coated Ceramic Membrane from Clay and Muntilan Sand for Wastewater Filter Application

“…It can be understood that for higher porosity a pores-pathway connecting from upper to lower ends has formed so the fluid can flow easily, otherwise, at lower porosity it has not formed. This is similar with conductivity in electricity that usually called percolation phenomenon the where the porosity of permeability rising sharply is called site percolation threshold and we have successfully explained this phenomenon using the percolation model [6]. However, further discussion about this model will not be addressed in this work.…”

“…The increase of permeability reduces the filtration performance due to easier the fluid and pollutant to flow and high adsorption of the clay to the pollutant as result of its high surface area [4]. In addition, the presence of titania outside the filter decomposes the pollutant by photocatalytic activity [6,13]. Therefore, this porous ceramic is very potential to be applied as wastewater filter.…”

“…However, because its grains are very small so the spaces between them, namely pores, are small too, ceramic clay has low permeability. To enlarge the pores, the usual way is adding a polymer [6], such as polyethylene glycol (PEG) as pores-agent that will decompose and evaporate out of the ceramic during burning process in the furnace at high temperature, and or inserting a material with different particle size. The aim of this work is to obtain a porous ceramic with adequate permeability for wastewater filter application using clay as abundant material inserted by Muntilan sand to improve the permeability and coated by titania for photocatalytic activity to decompose the pollutant.…”

Alkali-Activated Foams Coated with Colloidal Ag for Point-of-Use Water Disinfection

“…A compressive strength in the 0.9–1.7 MPa range and a flexural strength in the 1.0–4.7 MPa range are considered sufficient for materials intended for POU water treatment since these values ensure integrity in operating conditions. − These values can be obtained for all mixtures of foam samples [Figure c,d]. The mechanical strength of the porous body is dependent on the pore structure.…”