Effect of hypochlorite cleaning on the physiochemical characteristics of polyvinylidene fluoride membranes

Traditionally, the chemical cleaning is unanimously considered to be an effective means to restore membrane permeability. However, the chemical solutions can also be responsible for changes in membrane properties and thus affect the life-span of membranes. The aim of this study was to gain a better understanding of the effect of sodium hypochlorite cleaning solutions on the changes of physiochemical characteristics of microfiltration (MF) flat sheet membranes made from polyvinylidene fluoride (PVDF). A pilot-scale MBR was operated for 63 d and frequent and high dose sodium hypochlorite cleaning was carried out. The properties of the original and cleaned membranes were compared by pure water flux evaluation, contact angle measurement, mechanical testing, and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectra analysis. Effective removal of the foulant from the membrane surface resulted in more severe fouling. The pure water flux decayed faster with the extension of operation time and the membrane became more and more hydrophilic. The deterioration of ultimate tensile strength and the improvement of the ultimate elongation of membranes showed that membrane became more weak and flexible after hypochlorite cleaning. The results of ATR-FTIR indicated that the sodium hypochlorite cleaning had no vital damage to the chemical structure of PVDF membrane, but exerted impacts on its surface properties.

[1]  Elizabeth Arkhangelsky,et al.  Impact of chemical cleaning on properties and functioning of polyethersulfone membranes , 2007 .

[2]  V. Freger,et al.  TFC polyamide membranes modified by grafting of hydrophilic polymers: an FT-IR/AFM/TEM study , 2002 .

[3]  Anthony G. Fane,et al.  Fouling transients in nominally sub-critical flux operation of a membrane bioreactor , 2002 .

[4]  Zhen Zhou,et al.  Research and applications of membrane bioreactors in China: Progress and prospect , 2008 .

[5]  C. A. Smolders,et al.  Chemical treatment of membranes of a polymer blend: Mechanism of the reaction of hypochlorite with poly(vinyl pyrrolidone) , 1995 .

[6]  Y. Watanabe,et al.  Membrane biofouling in pilot-scale membrane bioreactors (MBRs) treating municipal wastewater: impact of biofilm formation. , 2007, Environmental science & technology.

[7]  H. Ng,et al.  Effects of solid retention time on the performance of submerged anoxic/oxic membrane bioreactor. , 2006, Water science and technology : a journal of the International Association on Water Pollution Research.

[8]  M. R. Bird,et al.  Solute-membrane fouling interactions during the ultrafiltration of black tea liquor , 2006 .

[9]  N. Gitis,et al.  Hypochlorite Cleaning Causes Degradation of Polymer Membranes , 2007 .

[10]  E. Gaudichet-Maurin,et al.  Ageing of polysulfone ultrafiltration membranes in contact with bleach solutions , 2006 .

[11]  M. Nyström,et al.  Characterization of cleaning results using combined flux and streaming potential methods , 1997 .

[12]  Viatcheslav Freger,et al.  Chemical cleaning of UF membranes fouled by BSA , 2005 .

[13]  D. Jenkins,et al.  Influence of mixed liquor properties and aeration intensity on membrane fouling in a submerged membrane bioreactor at high mixed liquor suspended solids concentrations. , 2007, Water research.

[14]  How Yong Ng,et al.  Membrane fouling in a submerged membrane bioreactor using track-etched and phase-inversed porous membranes , 2009 .

[15]  Robert M. Clark,et al.  Nanoscale probes for the evaluation of the integrity of ultrafiltration membranes , 2006 .

[16]  Yoshimasa Watanabe,et al.  Difference in membrane fouling in membrane bioreactors (MBRs) caused by membrane polymer materials , 2006 .

[17]  Zhiwei Wang,et al.  Membrane fouling in a submerged membrane bioreactor (MBR) under sub-critical flux operation : Membrane foulant and gel layer characterization , 2008 .

[18]  Zhichao Wu,et al.  Relationship between sludge characteristics and membrane flux determination in submerged membrane bioreactors , 2006 .

[19]  Zhiwei Wang,et al.  Characterization of dissolved organic matter in a submerged membrane bioreactor by using three-dimensional excitation and emission matrix fluorescence spectroscopy. , 2009, Water research.

[20]  Edward Bormashenko,et al.  Vibrational spectrum of PVDF and its interpretation , 2004 .

[21]  Pierre Aimar,et al.  Experimental study of the effects of hypochlorite on polysulfone membrane properties , 2006 .

[22]  Ewa Dluska,et al.  Reducing fouling and boundary-layer by application of helical flow in ultrafiltration module employed for radioactive wastes processing , 2009 .

[23]  P. Prádanos,et al.  Contact angles and external protein adsorption onto UF membranes , 1999 .

[24]  Yoshimasa Watanabe,et al.  Membrane fouling in pilot-scale membrane bioreactors (MBRs) treating municipal wastewater. , 2005, Environmental science & technology.

[25]  Seoktae Kang,et al.  Mitigated membrane fouling in a vertical submerged membrane bioreactor (VSMBR) , 2006 .

[26]  Yoshimasa Watanabe,et al.  The difference in characteristics of foulants in submerged MBRs caused by the difference in the membrane flux , 2008 .

[27]  A comparison of hydrodynamic methods for mitigating particle fouling in submerged membrane filtration , 2008 .

[28]  J. Keurentjes,et al.  Hydrophobicity measurements of microfiltration and ultrafiltration membranes. , 1989 .

[29]  S. Delgado,et al.  Effect of the shear intensity on fouling in submerged membrane bioreactor for wastewater treatment , 2008 .

[30]  M. R. Bird,et al.  The influence of hydrophobicity, roughness and charge upon ultrafiltration membranes for black tea liquor clarification , 2008 .

[31]  Cong-jie Gao,et al.  Study on hypochlorite degradation of aromatic polyamide reverse osmosis membrane , 2007 .