For treating ammonia nitrogen in wastewater using the liquid film method, what is a good surfactant to use?
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As the title suggests, there are many methods available for treating ammonia nitrogen in wastewater. Our company uses the liquid membrane extraction process, but the surfactants we use in this process are monopolized by the suppliers. Therefore, I am looking for experts who might know of alternative surfactant formulas that could be used as substitutes, so that we can work together on this.
We use the liquid membrane extraction process; we would appreciate guidance from colleagues with experience in this area.
The liquid film referred to by the poster is likely the emulsion liquid membrane process (emulsion liquid membrane extraction-stripping). This is the achievement of Dr. Nerman Li (an academician in three institutions in the Chinese mainland, Taiwan, and the United States, and the keynote speaker on the U.S. side at this year’s Sino-U.S. Chemical Engineering Conference), from the late 1960s. There are hardly any papers abroad researching this process at present. But domestically, this process has indeed been industrialized. I have been working on liquid membrane separation processes since 1988, but I have always held a critical attitude toward this process. Reason: 1. The process of emulsion formation and breakdown is complex ； 2. There is certainly some loss of the organic solvents and surfactants used for emulsification, even if it’s below 200 ppm; this represents new pollution ； For the treatment of ammonia-containing wastewater, 1. There are many interfering substances in the original wastewater, which affect emulsification and demulsification ； 2. Ammonia, as a polar small molecule, has low solubility in the membrane phase, which means a low mass transfer coefficient ； 3. The concentration of the resulting ammonium salt byproduct cannot be too high, which is determined by osmotic pressure and the stability of the emulsion film. In fact, as a membrane process, it is also used for ammonia removal, requires an increase in pH value, consumes sulfuric acid (or hydrochloric acid), and produces ammonium salts as by-products. The supporting gas membrane process performs better than the emulsion membrane process: there is no need for emulsification or demulsification, thus no loss of emulsifying components, and no additional consumption or pollution of wastewater ； It takes advantage of the high volatility of ammonia, rather than relying on the disadvantage of its low distribution coefficient between the aqueous and organic phases as in emulsion films ； The concentration of the resulting ammonium salt by-product can reach 20%, 25%, or even 35%, which facilitates the crystallization of the ammonium salt. The ammonia concentration can be reduced to 10, or even below 1 ppm. For information on the treatment of ammonia-containing wastewater, please see my post: Various new membrane technologies for the removal/recycling of ammonia from ammonia (ammonium or amine)-containing wastewater – just updated.
The person upstairs really has in-depth knowledge on this topic; a link to their post should be provided! ! !
Links to various new membrane technologies for the removal/recycling of ammonia (ammonium or amines) from ammonia-containing wastewater: http://bbs.hcbbs.com/thread-190731-1-1.html
Hello yjqin1, I was wondering when you will return to your home country; I would like to discuss with you the tests we have conducted on wastewater. Please give me a call when you return to your country.