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Volume 6, Number 2, March 2015

The presented research is about characterization of Cellulose Triacetate (CTA) based Polymer Inclusion Membranes (PIMs) which incorporated the commercial extractant Aliquat 336, Tributylphosphate (TBP) as modifier and 2-Nitro Phenyl Pentyl Ether (NPPE) as plasticizer, for the preparation of the membranes. Chemical and physical characteristics of the synthesized membranes especially membrane thickness and side difference effects were investigated. Different surface structures and membrane thickness affect the extraction efficiency of membranes. Membrane extraction experiments were studied where the glass-facing surface of the membranes placed next to feed phase and the air-facing surface to stripping phase. The membrane was characterized by means of AFM, FT-IR and SEM.

Key Words
characterization; polymer inclusion membrane; air-facing surface; glass-facing surface

(1) Aynur Manzak, Yasemin Yıldız:
Department of Chemistry, Sakarya University, Sakarya 54187, Turkey;
(2) Osman Tutkun:
Department of Chemical Engineering, Kyrgyzstan-Turkey Manas University, Bishkek, Kyrgyzstan.

In India, recycling of treated effluent plays a major role in the industry. Particularly in copper industry, recycling techniques for treated effluents adopt conventional technologies which are not energy efficient and recovery of high quality process water, free flowing salts and sludge's is very low. This paper presents an overview of enhanced modern technology for treated effluents in copper industry making it more efficient with high recovery of high quality process water and free flowing salts. Life cycle cost (LCC) would be 15-20% lower than the conventional technologies. The conventional technology can be replaced with this proposed technique in the existing and upcoming copper industries.

Key Words
copper industry; life cycle; recycling; waste water; improvised techniques

(1) Sankar Duraisamy, Rajagopal Saminathan:
Development consultants private limited, consulting engineers, Chennai-600006, TN, India;
(2) Deepa Narsimman:
Queen Mary's College (Autonomous), Chennai 600004, Tamil Nadu, India.

Salinity gradient power (SGP) systems have strong potential to generate sustainable clean electricity for 24 hours. Here, we introduce a solid-salt pressure-retarded osmosis (PRO) system using crystal salt powders rather than seawater. Solid salts have advantages such as a small storage volume, controllable solubility, high Gibbs dissolution energy, and a single type of water intake, low pretreatment costs. The power densities with 3 M draw solutions were 11 W/m2 with exothermic energy and 8.9 W/m2 without at 35 bar using a HTI FO membrane (water permeability A = 0.375 L m-2 h-1 bar-1). These empirical power densities are ~13% of the theoretical value.

Key Words
salinity gradient power; pressure-retarded osmosis; exothermic; calcium chloride; solid salt

(1) Harim Bae, Sung Jo Kwak, Nam Jo Jeong, Soon-Chul Park, Chul Ho Park:
Jeju Global Research Center (JGRC), Korea Institute of Energy Research (KIER), 200 Haemajihaean-ro, Gujwa-eup, Jeju Specific Self-Governing Province 695-971, South Korea;
(2) Wook Choi, Pravin G. Ingole, Hyung Keun Lee:
Greenhouse Gas Research Center, Korea Institute of Energy Research (KIER), 71-2 Jang-dong, Yuseong-gu, Daejeon 305-343, South Korea;
(3) Wook Choi, Jong Hak Kim:
Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-Ro, Seondaemun-Gu, Seoul 120-749 South Korea;
(4) Harim Bae, Jonghwi Lee:
Department of Chemical Engineering and Materials Science, Chung-Ang University, 221 Heukseok-Dong, Dongjak-gu, Seoul 156-756, South Korea.

Rejection of ionic solutes by reverse osmosis (RO) and nanofiltration (NF) membranes is controlled mainly by electrochemical interaction as well as pore size, but it is very difficult to directly evaluate such electrochemical interaction. In this work, we used an inverse HPLC method to investigate the interaction between ionic solutes and poly (m- phenylenediaminetrimesoyl) (PPT), a polymer similar to the skin layer of polyamide RO and NF membranes. Silica gel particles coated with PPT were used as the stationary phase, and aqueous solutions of the ionic solutes were used as the mobile phase. Chromatographs obtained for the ionic solutes showed features typical of exclusion chromatographs: the ionic solutes were eluted faster than water (mobile phase), and the exclusion intensity of the ionic solute decreased with increasing solute concentration, asymptotically approaching a minimum value. The charge density of PPT was estimated to be ca. 0.007 mol/L. On the basis of minimum exclusion intensity, the exclusion distances between a salt and neutralized PPT was examined, and the following average values were obtained: 0.49 nm for 1:1 salts, 0.57 nm for 2:1 salts, 0.60 nm for 1:2 salts, and 0.66 nm for 2:2 salts. However, NaAsO2 and H3BO3, which are dissolved at neutral pH in their undissociated forms, were not excluded.

Key Words
reverse osmosis; nanofiltration; polyamide; ionic solute; electrochemical interaction; HPLC

(1) Yoshiaki Kiso, Katsuya Hosogi:
Department of Environmental and Life Sciences, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8586, Japan;
(2) Yuki Kamimoto:
EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603, Japan;
(3) Yong-Jun Jung:
Department of Environmental engineering, Catholic University of Pusan, Oryundae-ro, Geumjeong-gu, Busan, 609-757, Korea.

This study aims to investigate the impacts of chemical cleaning on the performance of a reverse osmosis membrane. Chemicals used for simulating membrane cleaning include a surfactant (sodium dodecyl sulfate, SDS), a chelating agent (ethylenediaminetetraacetic acid, EDTA), and two proprietary cleaning formulations namely MC3 and MC11. The impact of sequential exposure to multiple membrane cleaning solutions was also examined. Water permeability and the rejection of boron and sodium were investigated under various water fluxes, temperatures and feedwater pH. Changes in the membrane performance were systematically explained based on the changes in the charge density, hydrophobicity and chemical structure of the membrane surface. The experimental results show that membrane cleaning can significantly alter the hydrophobicity and water permeability of the membrane; however, its impacts on the rejections of boron and sodium are marginal. Although the presence of surfactant or chelating agent may cause decreases in the rejection, solution pH is the key factor responsible for the loss of membrane separation and changes in the surface properties. The impact of solution pH on the water permeability can be reversed by applying a subsequent cleaning with the opposite pH condition. Nevertheless, the impacts of solution pH on boron and sodium rejections are irreversible in most cases.

Key Words
boron; reverse osmosis (RO); membrane cleaning; sodium dodecyl sulfate (SDS), ethylenediaminetetraacetic acid (EDTA)

(1) Kha L. Tu, Long D. Nghiem:
Strategic Water Infrastructure Laboratory and GeoQuEST Research Centre, School of Civil, Mining, and Environmental Engineering, University of Wollongong, NSW 2522, Australia;
(2) Allan R. Chivas:
GeoQuEST Research Centre, School of Earth and Environmental Sciences, University of Wollongong, NSW 2522, Australia.

Forward osmosis (FO) is an emerging membrane technology with potential applications in desalination and wastewater reclamation. The osmotic pressure gradient across the FO membrane is used to generate water flux. In this study, flux performance and foulant deposition on the FO membrane were systematically investigated with a co-current cross-flow membrane system. Sodium alginate (SA), bovine serum albumin (BSA) and tannic acid (TA) were used as model foulants. Organics adsorbed on the membrane were peeled off via oscillation and characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). When an initial flux of 8.42 L/m2h was applied, both flux reduction and foulant deposition were slight for the feed solution containing BSA and TA. In comparison, flux reduction and foulant deposition were much more severe for the feed solution containing SA, as a distinct SA cake-layer was formed on the membrane surface and played a crucial role in membrane fouling. In addition, as the initial SA concentration increased in FS, the thickness of the cake-layer increased remarkably, and the membrane fouling became more severe.

Key Words
forward osmosis; membrane fouling; permeate flux; adsorption

State Key laboratory of Pollution Control and Resources Reuse, Tongji University, Shanghai, 200092, China.

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