Cost effectiveness of conventionally and solar powered monovalent selective electrodialysis for seawater desalination in greenhouses

Abstract

Reverse osmosis is the most widely used desalination technology for treating irrigation water. Reverse omsosis removes both monovalent ions detrimental to crops (Na + , Cl − ) and divalent ions beneficial for crops (Ca 2+ , Mg 2+ , SO 2− 4 ).Fertilizer must then be added to the desalinated water to reintroduce these nutrients. Unlike reverse osmosis, monovalent selective electrodialysis selectively removes monovalent ions while retaining divalent ions in the desalinated water. This paper investigates the monovalent selectivity and cost effectiveness of the widely-used Neosepta and new Fujifilm monovalent selective electrodialysis membranes in treating seawater for irrigation. Membrane selectivity, limiting current, and resistance are experimentally characterized. These system parameters are inputs to the developed cost model, which determines fertilizer and water savings, as well as operating and capital costs, relative to reverse osmosis; the primary operating cost difference stems from reverse osmosis's significantly lower energy consumption.Given prices of commercially available membranes, monovalent selective electrodialysis costs an average of 30% more than reverse osmosis. At the projected sales price of Fujifilm membranes, which are still under development, monovalent selective electrodialysis costs an average of 10% more than reverse osmosis; if electricity costs are less than 0.08 $/kWh, monovalent selective electrodialysis is on par with reverse osmosis. Regardless of membrane price and electricity cost, solar-powered desalination is only economical if photovoltaic capital costs are significantly reduced to 0.10-0.20 $/kWh. When monovalent selective electrodialysis exceeds reverse osmosis cost, the financial requirements of competitive monovalent selective electrodialysis (e.g., energy consumption, electricity cost, energy source, membrane cost) are evaluated.

Sustainable Lithium Recovery from Hypersaline Salt-Lakes by Selective Electrodialysis: Transport and Thermodynamics

“…Our zeta potential measurements (Figure C) corroborate this observation, with the aged CEMs registering an average 24.7 mV decline and even switching signs at low pH. Compared to experiments with pristine IEMs, we consistently register attenuated Li + /Mg 2+ separation factors with aged IEMs, suggesting that irreversible damage of the PEI layer results from the salt-lake brine exposure, in agreement with recent reports . In essence, our results underscore the detrimental impact from the high concentration and acidity of salt-lake brines on the efficacy of Donnan exclusion for Li + concentration and accentuate the need to use representative multicomponent brines for selectivity characterization of novel IEMs.…”

“…At a solution pH of 7, under a feed salinity of 10, 30, and 70 g L –1 , the recorded current utilization for monovalent cation transport is 97.7, 96.6, and 91.1%, respectively, which are within 10% of empirical measurements with PEI-based CEMs. , The Na + /Mg 2+ and K + /Mg 2+ separation factors are 3.31 and 3.14 with a 10 g L –1 feed solution, and 2.23 and 2.30 with a 30 g L –1 feed solution, each falling within the respective uncertainty bounds from recent publications . The measured zeta potentials of the PEI layer of the CEM lie within the standard errors from prior streaming potential experiments …”

“…35,49 The Na + /Mg 2+ and K + /Mg 2+ separation factors are 3.31 and 3.14 with a 10 g L −1 feed solution, and 2.23 and 2.30 with a 30 g L −1 feed solution, each falling within the respective uncertainty bounds from recent publications. 78 The measured zeta potentials of the PEI layer of the CEM lie within the standard errors from prior streaming potential experiments. 49 The ion-exchange membranes are chemically stable for the solution pH between 0 and 8, 58 and all of our experiments were conducted within the stipulated pH range.…”

“…Compared to experiments with pristine IEMs, we consistently register attenuated Li + /Mg 2+ separation factors with aged IEMs, suggesting that irreversible damage of the PEI layer results from the salt-lake brine exposure, in agreement with recent reports. 78 In essence, our results underscore the detrimental impact from the high concentration and acidity of salt-lake brines on the efficacy of Donnan exclusion for Li + concentration and accentuate the need to use representative , between the pH range from 3 to 7. The beige and blue bands represent the expected separation factors for the solution pH between 3 and 7, for the Chilean and Chinese salt-lake brines, respectively.…”

Pilot-Scale Selective Electrodialysis for the Separation of Chloride and Sulphate from High-Salinity Wastewater

“…Studies have pointed out that the chemicals used in the pre-treatment process can also be a new source of fouling and have a negative impact on the nanofiltration process [15][16][17][18]. According to relevant studies, selective electrodialysis has advantages in terms of salt separation, treatment cost and resistance to membrane fouling [19][20][21], and has broad application prospects.…”