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The addition of synthetic flocculants to the bioreactor can increase the average particle size making microfiltration more efficient. When flocculants are not added, cakes form and accumulate causing low cell viability. Positively charged flocculants work better than negatively charged ones since the cells are generally negatively charged. [10]
Polyampholytes are polymers that contain both positively charged (cationic) and negatively charged (anionic) functional groups within the same molecule. Their unique structure allows them to exhibit amphoteric behavior, meaning they can interact with a range of substances depending on the surrounding pH, making them useful in applications like drug delivery, water treatment, and biomaterials.
Polyelectrolytes that bear both cationic and anionic repeat groups are called polyampholytes. The competition between the acid-base equilibria of these groups leads to additional complications in their physical behavior. These polymers usually only dissolve when sufficient added salt screens the interactions between oppositely charged segments.
Depending on the situation, polyelectrolytes can function as either flocculants or deflocculants. In order to stabilize emulsion, deflocculant polyelectrolytes are required. When repulsive forces between particles overcome the intermolecular forces in solution and the loose flocculated aggregates separate, deflocculation occurs. As opposed to ...
An automated device for determining the coagulant dose is the Streaming Current Detector (SCD). The SCD measures the net surface charge of the particles and shows a streaming current value of 0 when the charges are neutralized (cationic coagulants neutralize the anionic colloids). At this value (0), the coagulant dose can be said to be optimum. [1]
Long-chain polymer flocculants, such as modified polyacrylamides, are manufactured and sold by flocculant producers. These can be supplied in dry or liquid form for use in the flocculation process. The most common liquid polyacrylamide is supplied as an emulsion with 10-40% actives and the rest is a non-aqueous carrier fluid, surfactants and ...
Therefore, flocculants are often added to induce floc precipitation for easy filtration. ... Anionic: 10,000 – 1 million: Water treatment and paper production
Copolymerization of trimethylammoniumethyl acrylate chloride with acrylamide leads to high molecular weight cationic polyacrylamides, which are widely used as coagulants and flocculants [11] in waste water purification and as retention and dewatering agents in papermaking.