This paper describes a new concept of dense, dual-phase membrane consisting of two phases conducting, respectively, CO 3 2and electrons for selective permeation of CO 2 and O 2 at high temperatures. Membranes with a molten carbonate phase in a porous stainless-steel support were synthesized by a direct infiltration method. Membrane preparation conditions were optimized to obtain stable, gas-tight dual-phase membranes at high temperatures (>450 °C). The dual-phase membranes exhibit low single-gas permeance for pure CO 2 and N 2 (<5 × 10 -9 mol s -1 m -2 Pa -1 ) in 450-650 °C but substantially higher CO 2 permeance for CO 2 mixed with O 2 at high temperatures. CO 2 , after interacting with O 2 , transports through the molten carbonate phase in a form of CO 3 2-, with electrons transporting through the porous metal support. With further improvement, the dual-phase membranes may offer application in producing O 2 -enriched CO 2 streams for the oxyfuel combustion process. The concept can be also extended to prepare CO 2 perm-selective dense membranes for high-temperature CO 2 separation.
Sugarcane bagasse was partially acetylated to enhance its oil‐wicking ability in saturated environments while holding moisture for hydrocarbon biodegradation. The water sorption capacity of raw bagasse was reduced fourfold after treatment, which indicated considerably increased hydrophobicity but not a limited capability to hold moisture for hydrocarbon biodegradation. Characterization results by Fourier transform infrared (FT‐IR), scanning electron microscopy (SEM), X‐ray diffraction (XRD), and surface area analyzer suggested that treated bagasse exhibited enhanced hydrophobicity and surface area. Oil wicking test results indicate that treated bagasse is more effective in wicking oil from highly saturated environments than raw bagasse and suggest that application of this material in remediation of oil spills in highly saturated wetlands is promising.
The feasibility of reverse osmosis (RO) separation combined with ferrite reaction was investigated for the reclamation and recovery of heavy metals from metal plating wastewater. Disc tube-type RO modules were used for simultaneous purification and concentration of wastewaters containing zinc and chromium ions. A subsequent ferrite reaction was performed to recover zinc ions from RO concentrates. The operating conditions of the RO and ferrite reaction were determined in several lab-scale experiments with several types of model wastewater. Pilot-scale RO test results revealed that the zinc plating wastewater treated by one-pass RO and the chrome plating wastewater treated by two-pass RO were acceptable for preplating rinsewater. After ferrite reaction, 99.7% of zinc ions were recovered from the second-stage RO concentrate in the form of zinc ferrite, while significant amounts of chromium ions were retained in the concentrate. As a result of economic analysis, we suggested a retrofitting option, including a combined RO and ferrite process, for a wastewater treatment facility in a local metal plating company.
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