The difference between alum and activated carbon

Alum water purification is a common method in the past. Its principle is that alum can ionize two kinds of metal ions in water: KAl(SO4)2 = K++Al3++2SO42 and Al3+ are easily hydrolyzed to form colloidal aluminum hydroxide Al (OH) 3: Al3++3H2O = Al (OH) 3 (colloid) +3H+ hydrogen. It can adsorb suspended impurities in water, form precipitation and make water clear. So alum is a good water purifier. Activated carbon is a very fine carbon particle with a large surface area, and there are even smaller pores-capillaries in the carbon particle. This kind of capillary has a strong adsorption capacity, and carbon particles can fully contact with gas (impurities) because of their large surface area. When these gases (impurities) contact the capillary, they are adsorbed. Play a role in purification. It is very important to study the surface area of activated carbon. The test data of specific surface area of activated carbon can only be true and reliable by BET method. At present, many instruments in China can only do direct comparison tests, and now they have been eliminated in China. At present, the multi-point BET method is used to measure the specific surface area at home and abroad, and the standard for measuring the specific surface area at home and abroad is based on the BET method. Please refer to China's national standard (GB/T19587-2004)-a method for measuring the specific surface area of solid materials based on the BET principle of gas adsorption. Detection of specific surface area is actually a time-consuming work. Due to the different adsorption capacity of samples, the testing of some samples may take a whole day. If the testing process is not fully automated, testers can't always leave and concentrate. Observing the dashboard and manipulating the knob will lead to the failure of the test process, which will waste a lot of valuable time for testers. F-Sorb 2400 specific surface area tester is an instrument that truly realizes the function of BET method (with direct comparison method). More importantly, F-Sorb 2400 specific surface area tester is the only fully automatic intelligent specific surface area testing equipment in China so far. The test results are highly consistent with international standards and have good stability. At the same time, human error is reduced and the accuracy of test results is improved. The adsorption capacity of activated carbon for various gases (unit: mL/cm3) is H2, O2, N2, Cl2, CO2 4.5,35, 1 1, 494,97.