Ion Exchange-Assisted Electrodialysis for Treatment of Dilute Copper-Containing Wastes

Abstract

A novel process for electrodialysis of sodium chloride has been developed. This process allows the simultaneous and chlorine free production of high purity hydrochloric acid and caustic soda. The main result of this work is the substitution of chlor-alkali electrolysis, hydrogenchloride synthesis and absorption by electrodialysis. Special characteristic of the process is the use of a hydrogen consuming anode in a four chamber electrodialysis stack. The temperature rise due to the electrodialysis process is used to produce by vacuum evaporation high purity hydrochloric acid with a concentration of 36 mass-%. The major advantages of the process are the reduction of process steps, no production and handling of chlorine, a compact construction and low energy consumption.

Promoting the stability and adsorptive capacity of Fe3O4-embedded expanded graphite with an aminopropyltriethoxysilane–polydopamine coating for the removal of copper(ii) from water

“…The Cu(II) adsorption kinetics of the EGF, GFA, and GFA + KH550 were described well by the pseudo-second-order kinetic model (eqn (5), Fig. 4a).…”

“…where k intra (mg g À1 min À0. 5 ) is the intraparticle diffusion rate constant and C (mg g À1 ) is a constant related to the thickness of the boundary layer. 47 Meanwhile, the Langmuir and Freundlich models were used to determine the maximum adsorption capacity of the adsorbent.…”

“… 1 Since heavy metals are non-degradable and toxic, their removal from water through the development of safe biomaterials is continuing to attract a great deal of attention. 2 Various methods and techniques, such as chemical precipitation, 3 redox, 4 ion exchange, 5 flocculation, 6 adsorption, membrane filtration, electrodialysis, and photocatalysis 7,8 have been developed to remove copper (Cu( ii )) from wastewater. Here, the adsorption method is regarded as the most promising for Cu( ii ) removal, largely because of its operational simplicity, cost-effectiveness, and the possibility of regenerating the adsorbents.…”