Experimental Study on Chloride Ion Removal in High-Salt Wastewater System

Abstract

Chlorine is usually present in the environment in an ionic state, is highly mobile and difficult to degrade. High-chlorine wastewater can corrode buildings and affect the growth of animals and plants. Therefore, how to solve the environmental problem of high concentration of chloride ions well and effectively has drawn the intensive attention of the society. In this paper, chloride ion is removed from wastewater with the method of coprous chloride precipitation, and investigation is made on the effects of pH, temperature, amount of precipitant, titration time and reaction time on the removal efficiency of chloride ions. The results show that: when nCuSO4:nNa2SO3:nNaCl: n(ascorbic acid) =1.3:1.1:1: 0.01, and reaction pH is 3, temperature is 80 °C, titration time of sodium sulfite is 20min, reaction time after titration is 30min, the chloride ion has the optimal removal efficiency. SEM method is used for the characterization of the precipitates formed by the reaction. The results show that the experimentally produced complex cuprous chloride is irregular polyhedron with uneven particle size.

The Performance and Mechanism of a Mg-Al Double-Layer Oxide in Chloride ion Removal from an Aqueous Solution

“…Cl − concentration in this wastewater is much greater than 2000 mg L −1 , even up to 10,000 mg L −1 [ 3 ]. It is the high fluidity, activity, and stability of Cl − that make it difficult to remove [ 4 ]. Cl − can destroy the passive film to corrode the pipelines of the water circulation system when it has frequent exposure to metal [ 3 , 5 ].…”

“…Great effort has been made toward alleviating the dire situation of Cl − concentration in wastewater, including precipitation [ 3 , 4 , 6 ], evaporation and concentration [ 7 ], oxidation–reduction [ 8 , 9 ], and ion exchange [ 10 ]. However, it is worth noting that the methods described above are hard to practically apply to industrial wastewater due to prohibitive operating costs, inefficiency, limitations of treatment concentration, and a lack of suitable oxidants.…”

“…Their laminate elements are characteristically available in variable types and various proportions; changeable interlayer anions and controllable sizes also bring more possibility in terms of application of the materials [30,31]. Anions such as NO 3 − can be exchanged with CO 3 2− , SO 4 2− , and Cl − . In addition, LDHs that are calcined can undergo structural transformation and convert into metal oxides (LDOs) with thermal and chemical stability.…”