Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Flow-electrode capacitive deionization enables continuous and
  energy-efficient brine concentration   Many industrial and agricultural applications require the treatment of water
streams containing high concentrations of ionic species for closing material
cycles. High concentration factors are often desired, but hard to achieve with
established thermal or membrane-based water treatment technologies at low
energy consumptions. Capacitive deionization processes are normally assumed as
relevant for the treatment of low salinity solutions only. Flow-electrode
capacitive deionization (FCDI), on the other hand, is an electrically driven
water desalination technology, which allows the continuous desalination and
concentration of saline water streams even at elevated salinities. Ions are
adsorbed electrostatically in pumpable carbon flow electrodes, which enable a
range of new process designs.
  In this article, it is shown that continuously operated FCDI systems can be
applied for the treatment of salt brines. Concentrations of up to 291.5~g/L
NaCl were reached in the concentrate product stream. Based on this, FCDI is a
promising technology for brine treatment and salt recovery. Additionally, a
reduction of the energy demand by more than 70% is demonstrated by introducing
multiple cell pairs into a continuous FCDI system. While the economic
feasibility is not investigated here, the results show that FCDI systems may
compete with established technologies regarding their energy demand.

32
The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th
31
The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int
36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
30
The categories of this paper are: q-alg
35
The categories of this paper are: mtrl-th
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol
0
The categories of this paper are: hep-ph
37
The categories of this paper are: supr-con
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph