Recovery of lithium and boron from geothermal water by bipolar membrane electrodialysis (BMED) and ultrapure water production using electrodeionization (EDI)

This thesis is subdivided in two main parts: Simultaneous boron and lithium separations and recoveries using bipolar membrane electrodilaysis process (BMED) process and production of ultrapure water from RO permeate using electrodeionization (EDI) process. In the first part, parametric studies based investigation of the influence of applied electrical potential on simultaneous boron and lithium separations and recoveries and initial sample concentration by using ASTOM ACYLYSER EX3 BMED. In addition, the influence of applied electrical potential, sample solution volume and pH, acid and base compartments solutions composition was monitored using PCCell 64004 BMED system. Later on, both ASTOM and PCCell BMED systems were compared with Mega BMED system applied in their optimal operational conditions. All the systems tested were effective in simultaneous boron and lithium separations and recoveries. But each system showed differences in terms of optimal operational conditions to obtain maximum performance. In the second part, the applicability of electrodeionization method to produce ultrapure water from RO permeate of geothermal water. In studies, the effects of feed flow rate, electrical potential applied, cell number, type of ion exchange membranes and ion exchange resins employed on electrical conductivity, contents of boron, silicon and arsenic were investigated. In addition, recycle use of EDI system was studied.