Polyaluminum chloride (PAC) is an inorganic substance, a new water purification material and inorganic polymer coagulant, which has the properties of adsorption, coagulation and precipitation. The color is yellow or light yellow, dark brown, dark gray resinous solid. The product has strong bridging adsorption properties, and during the hydrolysis process, physical and chemical processes such as coagulation, adsorption and precipitation occur. The fundamental difference between polyaluminum chloride and traditional inorganic coagulants is that traditional inorganic coagulants are low molecular crystalline salts, while the structure of polyaluminum chloride is composed of polycarboxylate complexes with variable shapes, and the flocculation and precipitation speed is fast, suitable for Wide pH value range, non-corrosive to pipeline equipment, obvious water purification effect, can effectively remove color SS, COD, BOD and heavy metal ions such as arsenic and mercury in water, this product is widely used in drinking water, industrial water and sewage treatment fields .
Going to this standard, GB 15892-2020 "Polyaluminum Chloride for Drinking Water" replaces GB15892-2009 "Polyaluminum Chloride for Drinking Water". Compared with GB 15892-2009, the main technical changes are as follows:
1. The index of polyaluminum chloride for drinking water has been revised, and the indexes are more strictly required;
2. Added the determination of iron content, using the standard GB/T 22596-2008 "Water Treatment Agents - General Rules for the Determination of Iron Content";
3. Change the arsenic spot method in the determination of arsenic content to atomic fluorescence spectroscopy, and change the spectrophotometry in the determination of mercury content to atomic fluorescence spectroscopy. Atomic fluorescence spectroscopy has high sensitivity and wide linear range of the calibration curve , can carry out multi-element simultaneous determination, improve the work efficiency of testing institutions and testing personnel;
4. The determination of hexavalent chromium content is deleted;
5. The determination of chromium content has been increased, and electric heating atomic absorption spectrometry is used, among which graphite furnace atomic absorption spectrometry is commonly used, which has the advantages of strong selectivity, high sensitivity and wide analysis range;
6. Flame atomic absorption spectrometry is added to the determination of lead and cadmium content. Flame atomic absorption spectrometry also has the advantages of strong selectivity, high sensitivity and wide analysis range.