There is a misconsumption concept and awareness in our current understanding of household water treatment: as long as the “drinking” part meets the standard and other aspects of water use almost does not matter. In fact, in addition to drinking, domestic drinking water also includes eating, bathing, washing, and flushing toilets. In fact, one third of the various substances in the water are absorbed into the human body through the skin through bathing. Good water can improve the washing power of water, reduce the amount of washing powder, and reduce water pollution. Good water can also reduce the smell of toilet flushing and improve the indoor environment. Therefore, in addition to the “drinking” part, people’s water for bathing, washing, washing, etc. should also be clean, hygienic and free from pollution. Brown et al. studied the skin’s absorption of volatile organic compounds in water. According to adult drinking water 2 liters / day, infant drinking water 1 liter / day, the bathing time of both is 15 minutes / day, the skin absorption of common volatile organic compounds in drinking water and The oral intake ratio is 63/37 and 40/60 for adults and infants. Andelaman reported on indoor respiratory intake caused by trichloroethylene in drinking water. Based on the water consumption of 2 liters/person·day and the water consumption of bathing 40-95 liters/person·day, the respiratory intake of trichloroethylene during the shower is several times the oral intake of drinking water.
Therefore, the harm to human health caused by harmful substances in water is not simply caused by drinking. According to foreign reports, the proportion of harmful substances in water absorbed by the human body is roughly: 1/3 is absorbed by the oral cavity; 1/3 is absorbed by the skin during washing and bathing; 1/3 is absorbed by the respiratory tract along with water vapor during bathing.
There are many places where water is used in industry, and different treatment methods are used according to the quality of the water used to achieve the required standards. The industry-wide softening method is ion exchange.
Ion exchange water treatment refers to the use of ion exchangers to make the exchangeable ions in the exchanger and the aqueous solution produce reversible exchange in accordance with the amount of other substances, resulting in improved water quality and the structure of the exchanger is not substantial (chemical) Changing water treatment methods. In this water treatment method, only cations are involved in the exchange reaction, called cation exchange water treatment; only anions are involved in the exchange reaction, called anion exchange water treatment; both cations and anions are involved in the exchange reaction, called cation and anion exchange Water treatment. Because the quality of raw water varies greatly, and the requirements for effluent water quality are diverse, there are many types of ion exchange and a combination of water treatment methods. These water treatment methods are used to soften the raw water, remove alkali and salt. When the ion participating in the exchange reaction in the ion exchanger is sodium ion Na+, this method is called sodium (Na) type ion exchange method, this exchanger is called sodium (Na) type cation exchanger, similarly, there is hydrogen (H ) Type ion exchange method and hydrogen (H) type cation exchanger, etc.