Influence of additive contents on the properties of SiC ceramic membranes and their performance in oil‐water separation

Abstract

The high processing cost is the key challenge for the economic industrial use of SiC membrane The aim of this research was to fabricate mullite bonded porous SiC ceramic membrane at low temperature from novel combinations of fly ash and alumina (FA) in weight ratio 44.5:55.5 as sintering additives. The influences of FA and pore former content on the porosity, morphology, crystalline phase composition, mechanical performance, permeability properties were investigated. The membrane prepared at 1300 • C using 20 wt% FA showed pure water permeability 3690 Lm −2 h −1 bar −1 and exhibited high oil removal efficiency of ∼ 98% from the synthetic oil-water emulsion having oil concentration of 1000 mg/L. The corrosion behaviour of silicon carbide membrane in the strong acid and alkali solution and its mechanism were investigated. The utilization of fly ash successfully reduced the raw material cost and sintering temperature and the use of alumina reduced the amount of oxidation of SiC as well as increased the amount of mullite bond phase which resulted excellent mechanical strength to the final ceramics.

Application of coal fly ash based ceramic membranes in wastewater treatment: A sustainable alternative to commercial materials

“…The viscosity of the slurry is controlled using solvents like water and those with organic bases, such as acetone, to make it easier to spread over the carrier film and to increase the uniformity of the additives in the ceramic powder. Ceramic particles can be held together using binders such as polyvinyl alcohol [ [79] , [80] , [81] ], sodium metasilicate [ 82 , 83 ], carboxymethyl cellulose (CMC) [ 84 ], and others. The settling of the powder particles is prevented by the use of dispersants like sodium hexametaphosphate [ 34 ], sodium carbonate, and boric acid [ 82 ].…”

“…In order to make synthetic membranes more flexible, glycerine is mostly utilized as a plasticizer. The porous ceramic membrane's porosity is increased using pore-forming materials including dextrin [ 84 , 85 ], calcium carbonate [ 81 , 82 , 86 ], and spherical graphite [ 79 , 87 ] which decompose completely during the sintering process. Table 1 gives the properties, configurations, and fabrication techniques of some coal fly ash based ceramic membranes.…”

“… Polyvinyl alcohol (PVA) as a binder Whose apparent porosity 55.7 %, Flexural strength 8.5 MPa and [ 87 ] Kaolin-fly ash-based membranes Paste-casting method H 3 BO 3 and na 2 co 3 were used to provide homogeneity Calcium carbonate defines the pore morphology Sodium metasilicate (na 2 sio 3 .9h 2 o) acts as a binder. Porosity (∼34.36–39.0 %), pore size (∼0.65–1.81 μm) flexural strength (∼10–30 mpa) [ 83 ] SiC-Coal fly ash ceramic membranes dry pressing method Polyvinyl alcohol Graphite- pore former Porosity 54.46 % exhibited good, mechanical properties [ 79 ] Coal fly ash ceramic membrane extrusion method Dolomite used as a pore-forming Carboxymethyl cellulose (cmc) used as a binder Glycerin used as a plasticizer , Large particles reduced mechanical strength of fly ash based membranes while increasing porosity. [ 104 ] Lumina based tubular asymmetric membranes incorporated with coal fly ash Centrifugalcasting technique – Increased porosity and enhanced water permeability coincide with reduced mechanical strength and diminished linear shrinkage [ 105 ] High-aluminum coal fly ash ceramic membrane supports Uniaxial cold-pressing PVA solution as organic binder CaCO 3 pore forming agent Mechanical strengths 34–90 MPa [ 86 ] Coal fly ash-based tubular ceramic membrane Extrusion Dextrin as pore-forming agent CMC, as organic binder Glycerin, to improve the plasticity Porosity 38.9−45.9 % Mechanical strength 14.8−36.0 MPa [ 84 ] …”