Recovering ammonia from municipal wastewater by flow-electrode capacitive deionization

Fang, Kuo; Gong, Hui; He, Wenyan; Peng, Fei; He, Conghui; Wang, Kaijun

doi:10.1016/j.cej.2018.04.128

Cited by 121 publications

(37 citation statements)

References 40 publications

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“…However, TN and TP are actually nutrient resources for plant growth. In rural regions, where treated wastewater could be reused for agricultural irrigation, another option is to not remove nitrogen(N)/phosphorus(P) and instead reuse it as an alternative to chemical fertilizer [25,26]. In this case, the economic benefits caused by the reduced use of conventional fertilizer were also considered during the calculation of the expense for wastewater treatment.…”

Section: Data Sources and Economic Burden Calculation For Wastewater mentioning

confidence: 99%

Expected Rural Wastewater Treatment Promoted by Provincial Local Discharge Limit Legislation in China

Wang

Gong

2019

Sustainability

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Wastewater treatment in a rural region in China was undeveloped both in treatment capacity and legislation. The successful fast development of urban wastewater treatment plants (WWTPs) demonstrated the importance of legislation, including discharge limits. However, most provinces, with as high as 79.8% of the rural population in China, released no specific local discharge limits. Newly issued top-designed nationwide policy in September of 2018 by central China government required all provinces to issue their local rural wastewater discharge limits before June 2019. For the first time, this research analyzed the requirements of the newly issued policy and their inconsistence with several existing provincial limits. It proposed flexible principles for determination of discharge limits under various conditions to improve the rural residential environment as a whole. This study also proposed the use of the ratio between wastewater treatment cost and life expense to describe economic burden. Economic burden calculation for wastewater treatment in rural and urban regions was established respectively. Based on three conditions described in the new policy, the average burden for all urban residents was estimated as 0.122 ± 0.038% of the total life expense. In comparison, average nationwide rural burden was 0.087 ± 0.035% and 0.564 ± 0.196% for condition I (Total nitrogen(TN)/total phosphorus(TP) for resource recovery) and condition III (TN/TP for pollutant removal), respectively. It was also revealed that a stringent rural discharge limit lead to a Gini value as high as 0.38, indicting policy-related subsidies for rural residents should be carefully considered to ensure a balanced burden. Local discharge limit legislation and suitable financial policy is expected to promote rural wastewater treatment in China in the near future.

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Section: Data Sources and Economic Burden Calculation For Wastewater mentioning

confidence: 99%

Expected Rural Wastewater Treatment Promoted by Provincial Local Discharge Limit Legislation in China

Wang

Gong

2019

Sustainability

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“…Besides this process has been significantly improved by the researches on development of advanced materials of electrode, energy recovery, especially based on effective process designs, led this process be feasible for potable water production [8,9]. Aside from focusing on the generation of purified water, CDI also has a great potential for recovering mineral resources from water wastes [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. Using this technology, the charged species can be recovered by being adsorbed onto the electric double layers formed at the interface between an electrode and wastewater solution.…”

Section: Introductionmentioning

confidence: 99%

“…Most earlier studies with CDI for mineral recovery carried basic tests to evaluate adsorption capacity and selectivity of target species. Especially, the works on CDI for reclamation of nitrogen [10][11][12][13][14][15][16] from municipal wastewaters have been only recently performed considering the nutrients as one of the most possibly renewable target. The ionic ammonium which is faradaically separable was shown to be stably stored in the pores of carbon electrodes by the non-faradaic electrochemical CDI process [10].…”

Section: Introductionmentioning

confidence: 99%

“…The ammonium concentration in the brine solution was concentrated up to 322 mg-N/L via flow-electrode CDI allowing simultaneous removal and concentration of ammonia from the influent stream [12]. As the adsorption mechanisms in the CDI process has been widely studied, many solutions to optimize the performance and selectivity during nutrient recovery in CDI have been suggested.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Brine Water on Discharge of Cations in Membrane Capacitive Deionization and Its Implications on Nitrogen Recovery from Wastewater

Kim

Dorji

Gwak

et al. 2019

ACS Sustainable Chem. Eng.

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The ion desorption behavior from carbon electrodes onto high concentration brine was examined in this work because the ionic resources in brine are accumulated to attain high concentration in membrane capacitive deionization (MCDI) during mineral resource recovery. Several major issues were explored to demonstrate the suitability of MCDI for mineral recovery: ion discharge behavior using different solution chemistries (0 to 10 mM of NaCl, KCl, and MgCl2) of feed and brine, desorption efficiencies of various electrode regeneration methods (reverse polarity, short-circuiting and power disconnection) for enrichment of ions, and ion desorption selectivity among selected cations (Na, K, and Mg). The desorption efficiency was inversely proportional to ionic strength of aqueous brine solution as the ions from electrodes migrate toward the brine solution against ionic-strength gradient. Furthermore, the desorption onto brine was constrained by utilizing energy-efficient short-circuiting, whereas the electrochemically adsorbed ions were well discharged by reversing the polarity compensating for its cost. The ions were preferentially released from the electrodes in order of Na>K>Mg in the results, showing a reverse trend with the selectivity of electrosorption. From ammonium recovery tests, a high concentration of ammonium in brine (78.54 mg/L) was obtained from the synthetic wastewater through continuous operation of five cycles, attributing to its selective desorption over sodium ions present. However, it must be noted that its incomplete discharge from the electrodes is a challenging issue to overcome the limitations of MCDI as a mineral recovery process, and to attain highly concentrated ammonium.

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“…3.3.c, the Ti3C2Tx solution had a considerably lower (more negative) ζ-potential value of -27 mV, which resulted in electrode stability throughout the CDI operation. reported studies [18], [81], [82]. Due to the shorter charge-discharge times, Ti3C2Tx delivered 10 stable long-term cycles during the ~ 30 hour run time.…”

Section: Flow Electrode Slurry Characterizationmentioning

confidence: 98%

MXenes as Flow Electrodes for Capacitive Deionization of Wastewater

Mansoor¹

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The energy-water nexus poses an integrated research challenge, while opening up an opportunity space for the development of energy efficient technologies for water remediation. Capacitive Deionization (CDI) is an upcoming reclamation technology that uses a small applied voltage applied across electrodes to electrophoretically remove dissolved ionic impurities from wastewater streams. Similar to a supercapacitor, the ions are stored in the electric double layer of the electrodes. Reversing the polarity of applied voltage enables recovery of the removed ionic impurities, allowing for recycling and reuse. Simultaneous materials recovery and water reclamation makes CDI energy efficient and resource conservative, with potential to scale it up for industrial applications. The efficiency of the technology depends on the architectural design of the CDI cell, control of operating conditions, and the nature of the electrodes used. In this project we report on the performance of Ti3C2Tx MXenes flow electrodes in a CDI cell design. MXenes are a novel class of two-dimensional (2D) transition metal carbides, nitrides and carbonitrides with the general formula Mn+1XnTx where M is an early transition metal, X is carbon and/or nitrogen, Tx represents the surface terminations. Ti3C2Tx MXenes synthesized at Boise State, were employed as a flow electrode solution in an established CDI cell for targeted and selective ion removal. Performance metrics of achieved adsorption capacity, ion removal efficiency, regeneration efficiency, energy consumption, and charge efficiency, exceed those of currently prevalent electrode systems. In addition, rheological properties of the Ti3C2Tx MXenes colloidal solution were evaluated. This work establishes the deionization performance of Ti3C2Tx MXene based flow electrodes while providing further insight towards understanding the effect of structure and surface functionalization on the resultant deionization efficiency.

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Recovering ammonia from municipal wastewater by flow-electrode capacitive deionization

Cited by 121 publications

References 40 publications

Expected Rural Wastewater Treatment Promoted by Provincial Local Discharge Limit Legislation in China

Expected Rural Wastewater Treatment Promoted by Provincial Local Discharge Limit Legislation in China

Effect of Brine Water on Discharge of Cations in Membrane Capacitive Deionization and Its Implications on Nitrogen Recovery from Wastewater

MXenes as Flow Electrodes for Capacitive Deionization of Wastewater

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