In this paper, two series of poly(sulfobetaine methacrylate)- b-poly(lauryl methacrylate) (PSBMA- b-PLMA) diblock copolymers were prepared to investigate the core-shell reversion of amphiphilic copolymers. Experimental results proved that the PSBMA- b-PLMA copolymers can be self-assembled as core-shell nanoparticles in chloroform. Moreover, 1H NMR spectra and contact angle measurements revealed that there is a transitional PSBMA/PLMA block ratio of 0.6, above which the nanoparticles are capable of switching their core and shell in aqueous solution. Consequently, nanoparticles with PSBMA/PLMA block ratios above 0.6 showed superior antifouling and antibacterial abilities to those with block ratios below 0.4. Moreover, it was also found that the block chain length plays an important role in core-shell reversion as evidenced by 1H NMR spectra, water contact angle, and antifouling tests. As a result, coatings fabricated with the PLMA100 series of nanoparticles showed better antifouling abilities than those of the PLMA150 series at the same block ratio probably because of the thinner shell of PLMA100 copolymers. PSBMA100- b-PLMA100 was proved to be the best candidate for the fabrication of antifouling coatings as it exhibited the highest efficacy in antibacterial adhesion and antiprotein adsorption. This study provided a facile method to fabricate antifouling coatings by developing amphiphilic diblock copolymers with tuned hydrophobic/hydrophilic block ratio, block chain length, etc.

This work is a comprehensive study on removal of phenols from coal gasification wastewater (CGW) through a polypropylene hollow fiber supported liquid membrane (HF-SLM). Factors affecting removal of phenols such as composition of liquid membrane phase, design of mass transfer process, proportion of organic phase in feed phase and stripping phase, feed phase pressure, system temperature, were investigated. The operating conditions obtained for the removal of phenols are as follows: mixture of 20% tributyl phosphate and 80% kerosene as liquid membrane phase, system temperature 20°C, feed phase went through tube side, stripping phase went through shell side, organic phase proportion in feed phase 2%, countercurrent flow for feed phase and stripping phase, feed phase pressure 0.015MPa. Under the optimum conditions, a removal rate of phenols was obtained exceeding 90% after 120min. These results suggest that HF-SLM could be promising in removal of phenols from CGW.

Supported liquid membrane (SLM) has received great attention in recent years. However, very few SLM system could be amplified from the lab to large-scale applications due to insufficient membrane stability. In the present work, a facile surface modification tactic that focused on improving the hydrophobicity of polypropylene hollow fiber membrane (PP-HFM), the support of SLM, by grafting heptadecafluoro-1,1,2,2-tetradecyltrimethoxysilane (FAS) and SiO2 was studied. The influence of hydrophobic modification on the stability of SLM was investigated. The PP-HFM was characterized by SEM, ATR-FTIR and contact angle to test the effects of modification. The analysis results revealed the changes in the surface morphology, chemical composition and hydrophobicity of the membrane. Under optimum modified conditions (0.03mol/L FAS and 0.15% SiO2), the contact angle increased greatly from 92.1° to 132.2° after modification. Therefore, the SLM with modified PP-HFM as the support showed significant enhancement in stability. The average phenol removal percentage could be maintained at 75.32% in 16days of continuous pilot-scale experiments.

The applications of photo-fermentative bacteria (PFB) for continuous hydrogen production are generally subjected to a serious biomass washout from photobioreactor, resulting from poor flocculation of PFB. In this study, through reducing the absolute zeta-potentials of PFB, Ca2+ greatly decreased total interaction energy barrier of PFB based on DLVO theory, thus promoted the bioflocculation of Rhodopseudomonas faecalis RLD-53. Average floc size of PFB increased with the Ca2+ concentration, and reached maximum 30.07 mu m at 4 mmol/l. Consequently, biomass retention capacity of photobioreactor significantly enhanced after 30 min settling with half working volume discharge. In the continuous photo-fermentative sequencing batch reactor, compared with the free cell culture, bioflocculation reached a higher steady-state hydrogen production rate of 879 ml H-2/l/d and hydrogen yield of 2.64 mol H-2/mol acetate, respectively. Therefore, bioflocculation promoted by calcium ion was an effective strategy for retaining PFB in photobioreactor to produce hydrogen continuously. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.