The impacts of membrane degradation due to chlorine attack on the rejection of inorganic salts and trace organic contaminants by nanofiltration (NF) and reverse osmosis (RO) membranes were investigated in this study. The rejection of trace contaminants was examined at environmentally relevant concentrations. Changes in the membrane surface morphology were observed as a result of chlorine exposure. A small increase in rejection was consistently observed with all four membranes selected in this study after being exposed to a low concentration of hypochlorite (100 ppm). In contrast, a higher concentration of hypochlorite (i.e., 2000 ppm) could be detrimental to the membrane separation capacity. Membranes with severe chlorine impact showed a considerable decrease in rejection over filtration time, possibly due to rearrangement of the polyamide chains under the influence of chlorine degradation and filtration pressure. The reported results indicate that loose NF membranes are more sensitive to chlorine exposure than RO membranes. The impact of hypochlorite exposure (both positive and negative) on rejection is dependent on the strength of the hypochlorite solution and is more significant for the neutral carbamazepine compound than the negatively charged sulfamethoxazole.
nanofiltration; reverse osmosis; water recycling; hypochlorite; membrane degradation; trace organic contaminants
School of Civil Mining and Environmental Engineering, The University of Wollongong, Wollongong, NSW 2522, Australia.
The study contributes in the treatment of waste generated by the textile complex cotton of Draa Ben Khedda, Algeria. The azo dye \"Direct Red Solophenyle 4GE\" represents the base particle of the discharges and electrocoagulation with nanofiltration are used as a means of treatment. The solar photovoltaic is suitable for electrochemical process to reduce the energy cost. Several study parameters are considered in this work. The electrocoagulation batch gives the best reduction 37% for a dye concentration of 7.21 mg/L ([NaCl]added = 1 g/L; j = 25.2 mA/cm2). Coupling methods (electrocoagulation-nonofiltration) gives a complete discoloration rejecting concentration 52.4 mg/L (pHi = 7.6, [NaCl]added = 3 g/L, j = 2.13 mA/cm2). The result shows the coupling efficiency with a reduced amount of resulting slurry at the end of treatment.
rejection textile; aluminium electrodes; elecotrocoagulation; nanofiltration; organic membrane; solar photovoltaic
(1) Zerrouki Djahida, Taleb Ahmed Mourad, Maachi Rachida:
USTHB, Environment Engineering Department, BP 32 El Alia 16111 Algiers, Algeria;
(2) Djelal Hayet:
School of Crafts Environment, Campus de Ker Lann, 35170 Bruz, France;
(3) Djelal Hayet:
European University of Brittany, Rennes, France.
Pervaporation is the most promising technique for the recovery of ethanol from the fermentation system. To date, extensive research has been conducted on the exploration of membrane materials with favorable properties. In this paper, we primarily review the performance of adsorbent-filled rubbery membranes. In addition, the fundamental mechanisms of ethanol and water molecules transportation through composite membranes are demonstrated, particularly from the perspective of cluster formation. Finally, future prospects are also analyzed to develop the guidelines for the future development of excellent membrane materials for ethanol concentration. This paper is not meant to be an exhaustive overview, rather a specialized summary that allows readers to select the information appropriated to their topics.
mixed matrix membranes; pervaporation; ethanol; PDMS; cluster
(1) Ling-Yun Ji, Bao-Li Shi:
Department of Chemistry, College of Science, Northeast Forestry University, Harbin, 150040, China;
(2) Bao-Li Shi, Qing-Wen Wang:
Key Laboratory of Bio-Based Material Science and Technology of Ministry of Education, Northeast Forestry University, Harbin, 150040, China.
The present work aimed to study the decolorization kinetics and characteristics of a selected azo dye under the influence of two key operational parameters including hydraulic retention time (HRT) and solid retention time (SRT). The decolorization efficiency and the two important criteria of k and normalized k (k/MLSS) were evaluated in lab-scale membrane sequencing batch reactors (MSBRs) at various HRTs of 48, 24 and 16 h (with constant SRT) and in addition, at various SRTs of infinity, 40 and 10 d (with constant HRT). According to the obtained results, both zero and first-order kinetics were properly fitted the decolorization profiles of the selected azo dye in all of the applied HRTs and SRTs. Increase of both HRT and SRT positively affected the decolorization efficiency. More MLSS concentrations corresponded to the lower HRTs and the higher SRTs resulted in higher decolorization rate constants (k). However, the effect of reducing the HRT was not compensated by increase of the MLSS concentration in order to reach higher decolorization efficiency. In addition, increase of the decolorization efficiency, as a consequence of the higher MLSS concentrations at longer SRTs, was restrained by decrease of the time-limited decolorization capability of biomass (represented by normalized k). Evaluation of both k and normalized k is suggested in order to have a more precise study on the decolorization kinetics and characteristics.
decolorization kinetics and characteristics; hydraulic retention time; solid retention time; decolorization rate constant (k); normalized k
Civil and Environmental Engineering Department, Amirkabir University of Technology, Hafez Ave., Tehran15875-4413, Iran.
Adipic acid (hexane-1,6-dioic acid) is one of the most used chemical in industrial applications. This must be separated from any environmental contaminant. In this study, adipic acid separation from wastewater by adsorption method onto Perlite or Perlite + Mn or Perlite + Cu composites was investigated. Adsorption of Adipic acid was investigated in terms of equilibrium, and thermodynamic conditions. For thermodynamic investigations the experiments carried out at three different temperatures (298 K, 318 K, 328 K). In the equilibrium studies, 2 g of perlite and its composites were determined as the optimal adsorbent amount. Freundlich and Langmuir isotherms were applied to the experimental data. Freundlich isotherms for all temperatures used in this work gave some deviations with R square values under 0.98 where as Langmuir isotherm gave good results with R square values upper 0.99 at different temperatures. As a result of thermodynamic studies, adsorption enthalpy (ΔH), adsorption entropy (ΔS), and adsorption free energy (ΔG) have been calculated for each adsorbents.
adsorption; adipic acid; perlite; manganese; copper
(1) Hasan Uslu:
Beykent University, Engineering and Architecture Faculty, Chemical Engineering Department, Ayazağa Īstanbul, Turkey;
(2) Gőksel Demir:
Bahçeşehir University, Engineering Faculty, Environmental Engineering Department, BeşiktaşĪstanbul, Turkey;
(3) Cuma Bayat:
Īstanbu Esenyurt University, Engineering and Architecture Faculty, Industrial Engineering Department, Esenyurt, Istanbul, Turkey;
(4) Kailas L. Wasewar:
Advance Separation and Analytical Laboratory (ASPAL), Department of Chemical Engineering, Visvesvaraya National Institute of Technology, Nagpur-440010 (M.S) India;
(5) Hisham S. Bamufleh:
Department of Chemical & Materials Engineering, Faculty of Engineering, King Abdulaziz University, P.O. Box 80204, Jeddah 21589, Saudi Arabia.