Study on effects of different organic compounds on solubility and metastable zone of sodium chloride

：In the process of zero discharge of wastewater，the existence of organic matter has an adverse effect on crystallization of inorganic salt. Therefore，it is necessary to study the effect of organic additives on salt crystallization. The solubility，supersolubility and variation of the metastable zone（MSZW） of sodium chloride in pure water and aqueous solution that added peptone，phenol and heptanediacid were measured in this paper. The results showed that the existence of the three organic matters decreases the solubility of sodium chloride. The solubility decreases with the increase of organic concentration. The effect of heptanediacid is the largest. All the organic additives doped in sodium chloride will narrow the MSZW，and the degrees of the organic additives are in the order as follows：phenol＞heptanediacid＞peptone. In the phenol aqueous solution with saturated temperature of 343.15K and COD of 20000mg/L，the width of MSZW can be reduced by 65.3% compared with that in pure water. The faster the stirring rate and the lower the cooling rate，the narrower the MSZW. In the presence of different organic matters，the order of the influence of stirring rate on the MSZW as follows：heptanediacid＞peptone＞phenol，the order of the influence of cooling rate on the MSZW as follows：peptone＞phenol＞heptanediacid. © 2017, Chemical Industry Press Co., Ltd.. All rights reserved.