Abstract
Methyl tert-butyl ether (MTBE) is a widely used gasoline additive that has high water solubility, and is difficult to separate from contaminated ground and surface waters. We present the development in functionalized carbon nanotube-immobilized membranes (CNIM-f) and graphene oxide-immobilized membranes (GOIM) for enhanced separation of MTBE via sweep gas membrane distillation (SGMD). Both types of modified membranes demonstrated high performance in MTBE removal from its aqueous mixture. Among the membranes studied, CNIM-f provided the best performance in terms of flux, removal efficiency, mass transfer coefficients and overall selectivity. The immobilization f-CNTs and GO altered the surface characteristics of the membrane and enhanced partition coefficients, and thus assisted MTBE transport across the membrane. The MTBE flux reached as high as 1.4 kg/m2 h with f-CNTs, which was 22% higher than that of the unmodified PTFE membrane. The maximum MTBE removal using CNIM-f reached 56% at 0.5 wt % of the MTBE in water, and at a temperature of 30 °C. With selectivity as high as 60, MTBE recovery from contaminated water is very viable using these nanocarbon-immobilized membranes.
Highlights
Over 20 million tons of methyl tert-butyl ether (MTBE) is produced and used as a fuel additive around the world every year, and it has contaminated ground and surface water all across the globe [1,2]
Methyl tert-butyl ether (MTBE) is highly water soluble, has a low Henry’s Law constant and low sorption constants [2]. These properties enhance the mobility of MTBE, and make it difficult to separate from water. Methods such as air stripping, adsorption, oxidation processes and pervaporation have been used for MTBE removal [10,11,12]
We have reported a membrane modification approach using carbon nanotubes (CNTs), functionalized CNTs (f-CNTs) and Graphene oxide (GO) [29,30,31,32,33] to improve the characteristics of the membrane, and have shown an excellent adsorption and transport of solutes, leading enhanced flux and selectivity in desalination, as well as the separation of organic solvents from aqueous mixtures [21,23,31]
Summary
Over 20 million tons of methyl tert-butyl ether (MTBE) is produced and used as a fuel additive around the world every year, and it has contaminated ground and surface water all across the globe [1,2]. MTBE is highly water soluble, has a low Henry’s Law constant and low sorption constants [2] These properties enhance the mobility of MTBE, and make it difficult to separate from water. Methods such as air stripping, adsorption, oxidation processes and pervaporation have been used for MTBE removal [10,11,12]. Air stripping is the conventional method for separating MTBE from water. This approach works well only at high temperature, which is energy extensive, and lowering the temperature of MTBE-contaminated feed water can reduce the efficiency of this technology significantly. The results show a high separation factor for MTBE [17], the process has relatively low permeate flux [18]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
