Weak Acid Cation Resin
Weak acid cation exchange resins refer to a type of ion exchange resin containing weak acid groups such as carboxyl (-COOH). The properties of weak acid cation exchange resins in water are similar to that of weak acid and can dissociate H+. The dissociated negatively charged groups can be adsorbed and combined with other cations in the solution to produce an exchange effect. However, due to its weak dissociation, it is difficult to perform ion exchange at low pH values, and can only react with alkaline, neutral or slightly acidic salts. In addition, because the weak acid cation exchange resins have a greater affinity for H+, they are easier to regenerate and very suitable for stratified beds.
Weak acid cation exchange resins can be used for the removal of Pb(II) from industrial wastewater. Precipitation is commonly used to remove Pb from wastewater due to the simplicity of the process and for economic reasons. However, precipitation methods require the use of chemicals and lead to the formation of large amounts of sludge. In addition, difficulties in the liquid-solid separation step limit the large-scale application of the method. Selectivity, recovery of metal ions, low amount of sludge formation and ability to reach toxicity limit values at low influent concentrations are the advantages of ion exchange processes.Weak acid cation exchange resins with high affinity for divalent cations (Pb(II), Cu(II), Zn(II), etc.) and high adsorption capacity, as well as simple regeneration process and less use of chemicals, make them an important alternative to precipitation methods.( Vergili I , et al., 2017) Weak acid cation resins can also be used to extract colistin sulfate. Colistin sulfate is a kind of basic polypeptide antibiotic, mainly used to prevent and control the infection of sensitive bacteria and promote the growth of livestock and poultry. The extraction and separation methods of colistin sulfate mainly include adsorption method, precipitation method, solvent extraction method and ion exchange method. Among them, the ion exchange method is the most widely used. The products used internationally include DOW's Amberlite FPC3500 resin and so on. But its price is higher, and Alfa Chemistry can provide similar weak acid cation exchange resins with comparable performance and cheap prices.
- Water softening
- Purification of antibiotics
- Separation of metal
- Refining of white sugar
- Vergili I , et al. Sorption of Pb (II) from battery industry wastewater using a weak acid cation exchange resin[J]. Process Safety & Environmental Protection, 2017.