An innovative beneficial reuse of seawater concentrate using bipolar membrane electrodialysis

Simultaneous regeneration of inorganic acid and base from a metal washing step wastewater by bipolar membrane electrodialysis after pretreatment by crystallization in a fluidized pellet reactor

“…The generation of acid and base not only brings benefits for environmental protection but also is a valuable source of chemicals, which can be used in metal industry such as pickle liquor in steel industries, zinc and copper electroplating industries [25,26], the nickel processing plant where the wastewater was generated and the wastewater treatment plant itself to reduce the risks and costs related to transportation and storage of acid and base [12]. Moreover, part of the contaminants in the feed is also removed by applying EDBM.…”

“…A bipolar membrane typically consists of two contacting, oppositely-charged ion exchange layers, producing hydroxide ions and protons that combine with cations and anions in wastewater to form acid and base, respectively [5,6]. EDBM can be used in several applications such as chemical processing (inorganic and organic acid/base production) [7][8][9], process integration (isolation of organic acids, food sector) [10,11] and pollution control (salt removal, acid/base regeneration) [12][13][14]. For acid/base regeneration from wastewater such as reverse osmosis (RO) concentrates [12] and spent caustic solutions [13], EDBM is thought feasible to split the salt in the wastewater into acid and base.…”

“…EDBM can be used in several applications such as chemical processing (inorganic and organic acid/base production) [7][8][9], process integration (isolation of organic acids, food sector) [10,11] and pollution control (salt removal, acid/base regeneration) [12][13][14]. For acid/base regeneration from wastewater such as reverse osmosis (RO) concentrates [12] and spent caustic solutions [13], EDBM is thought feasible to split the salt in the wastewater into acid and base. Yang et al reported the continuous regeneration of mixed acid and sodium hydroxide from RO concentrate up to 1 M at a current density of 57 mA/m 2 , a flow rate of 0.3 L/h and total membrane surface of 264 cm 2 .…”

“…Yang et al reported the continuous regeneration of mixed acid and sodium hydroxide from RO concentrate up to 1 M at a current density of 57 mA/m 2 , a flow rate of 0.3 L/h and total membrane surface of 264 cm 2 . Two advantages were achieved: the produced acid was reused for RO system pretreatment and the contaminants were removed from RO concentrate to protect the aquatic environment [12]. Wei et al regenerated sodium hydroxide from spent caustic stream of petrochemical industry [13] at a current density of 50 mA/cm 2 , the effective membrane area of 7.07 cm 2 and an initial base concentration of 0.1 M. They showed that the current efficiency was over 90% at an energy consumption of 8.2 kW h/kg NaOH and a process cost of 0.97 USD/kg NaOH.…”

The treatment of cyanide from gold mine effluent by a novel five-compartment electrodialysis

“…They were installed in a laboratory-scale ED stack. The whole experimental set-up was fixed by brackets in stainless steel, which was purchased from Shandong Tianwei Membrane Technology Co., Ltd (Shandong, China) [42].…”