Low cost pyrrhotite ash/clay-based inorganic membrane for industrial wastewaters treatment

• Published in: Journal of environmental chemical engineering Vol. 8; no. 1; p. 103646
• Main Authors: Hatimi, B., Mouldar, J., Loudiki, A., Hafdi, H., Joudi, M., Daoudi, E.M., Nasrellah, H., Lançar, I.-T, El Mhammedi, M.A., Bakasse, M.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.02.2020
• Subjects: Ceramic membrane; Natural clay; Pyrrhotite ash; Wastewater treatment; Ceramic membrane; Natural clay; Wastewater treatment; Pyrrhotite ash
• ISSN: 2213-3437; 2213-3437
• DOI: 10.1016/j.jece.2019.103646

[Display omitted] •Highly hydrophobic low cost membrane was successfully developed based on pyrrhotite ash and natural kaolin clay.•Pyrrhotite ash solid waste was characterized using X-Ray fluorescence, X-Ray diffraction, TGA/DCS analyses.•The impact of pyrrhotite ash amount and sintering temperature on membrane mineralogy, morphology and proprieties was studied.•The developed membrane provides almost total reduction of turbidity, oil and fat in tannery and dairy wastewater samples. The elaboration and optimization of a low-cost microfiltration membrane based on natural clay and pyrrhotite ash solid waste were performed leading to a change in the membrane surface morphology and improved its hydrophobicity. The impact of pyrrhotite ash fraction and sintering temperature on mineralogy, morphology, porosity, permeability, mechanical strength and corrosion resistance was evaluated. The highest values of permeability and mechanical strength were 22.88 10−7  m3/h m².kPa and 27.42 MPa respectively, for the membrane prepared with 50 % of pyrrhotite ash and sintered at 1000 °C. Two different tannery and dairy industrial wastewaters were tested. The filtration efficiency at different transmembrane pressures was evaluated by the rejection rate of turbidity, conductivity, pH, oil and fat. The performance of conventional treatment such as sedimentation compared to MF confirmed that the elaborated membrane consists the best alternative, with a removal rate of organic oil and fat about 94 %, and practically a total reduction of water turbidity up to 100 %, compared to sedimentation with only 15 % and 72 % respectively, the conductivity of permeate was not much different from the conductivity of the raw wastewater, and only a few percent for chrome. Additionally, the four models of Hermia were adopted to study the membrane fouling phenomena where the cake formation model fits best to the flow decline experimental data during the filtration of both effluents. The process developed in this investigation can be considered an eco-friendly one since it tends to valorize the pyrrhotite ash solid waste and preserve natural clay, moreover, it staves off energy waste by avoiding dry step during the thermal treatment of ceramics.