Regeneration of pilot-scale ion exchange columns for hexavalent chromium removal

Korak, Julie A.; Huggins, Richard G.; Arias‐Paić, Miguel

doi:10.1016/j.watres.2017.03.018

Cited by 112 publications

(46 citation statements)

References 19 publications

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“…But tuning the oxygen vacancy of Zn−Cr spinel is rarely reported. Moreover, the use of Zn−Cr mixed oxides will possibly be limited due to the environmental risk of hexavalent chromium . In this context, an alternative and environmentally friendly oxide with tunable oxygen vacancy may be preferentially favoured by this process.…”

Section: Figurementioning

confidence: 99%

Ceria‐Zirconia/Zeolite Bifunctional Catalyst for Highly Selective Conversion of Syngas into Aromatics

et al. 2018

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Ceria‐zirconia solid solutions with tunable surface oxygen vacancy have been used in the direct conversion of syngas into aromatics after coupling with ZSM‐5 zeolite. A high selectivity of 83.1 % to aromatics has been achieved from syngas with low H2/CO ratio over Ce0.2Zr0.8O2/ZSM‐5 bifunctional catalyst. The surface oxygen vacancy of Ce0.2Zr0.8O2 is supposed to facilitate the formation of oxygenates which act as intermediates for C−C coupling and aromatization on ZSM‐5, and thus contribute to the well kinetic matching between C−O activation and C−C coupling over these two components of catalyst. The ceria‐zirconia with abundant surface oxygen vacancies and enhanced lattice oxygen mobility intimately mixed with ZSM‐5 zeolite with moderate acidity and crystal size play an important role in the catalytic performance.

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Section: Figurementioning

confidence: 99%

Ceria‐Zirconia/Zeolite Bifunctional Catalyst for Highly Selective Conversion of Syngas into Aromatics

et al. 2018

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“…While a new Cr(VI) maximum contaminant level (MCL) would have widespread impacts, existing US Environmental Protection Agency (USEPA) and California MCLs for total chromium (Cr(T)) of 0.100 and 0.050 mg/L, respectively, in combination with progressive drinking water providers, continue to drive ongoing research and development. In particular, progress has been made recently for Cr(VI) removal from groundwater using strong base anion (SBA) exchange through regeneration optimization, waste brine minimization, regenerant recovery through nanofiltration, optimization of operational conditions, and new resin testing (Gorman, Seidel, Henrie, Huang, & Thompson, ; Korak, Huggins, & Arias‐Paic, ; Korak, Huggins, & Arias‐Paic, ; Plummer et al, ). As an alternative to SBA exchange, recent progress has also been made in Cr(VI) treatment using the reductant stannous chloride (SnCl 2 ) (Henrie et al, ; Kennedy, Korak, Flint, Hoffman, & Arias‐Paic, ).…”

Section: Introductionmentioning

confidence: 99%

Stannous chloride reduction–filtration for hexavalent and total chromium removal from groundwater

Kennedy

Croft²,

Flint

et al. 2020

AWWA Water Science

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Hexavalent chromium (Cr(VI)) reduction using stannous chloride (SnCl 2 ) has emerged as a possible alternative to chromium treatment technologies such as strong base anion exchange. In an effort to target not only Cr(VI) reduction but, ultimately, total chromium (Cr(T)) removal, SnCl 2 addition followed by rapid sand filtration was tested at the pilot scale on a groundwater with a naturally occurring Cr(VI) concentration of 0.090 mg/L. A SnCl 2 dose of 1.5 mg/L, followed by filtration, was able to consistently remove Cr(T) to less than 0.010 mg/L following an initial ripening period, with limited head loss for 10 sequential 17-to 25-hr filter runs. Total tin and turbidity removal were similar, decreasing to below 0.050 mg/L and raw water levels, respectively. Analysis of filter sand following backwashes and three different material pipe segments that were exposed to unfiltered water dosed with SnCl 2 indicated the accumulation of Cr and Sn on surfaces, which remains a concern.

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“…In addition to boiler feedwater treatment, IX is used as pretreatment for reverse osmosis to reduce inorganic fouling when treating coal seam gas wastewater [6]. Outside of oil & gas, IX is used in various water treatment applications including dissolved organic carbon removal [7], water softening [8,9], trace metal and nitrate removal [10][11][12] and wastewater treatment to meet effluent discharge [13,14].…”

Section: Steam Is Used In a Variety Of Ways Includingmentioning

confidence: 99%

Evaluation of new ion exchange resins for hardness removal from boiler feedwater

et al. 2018

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Ion exchange is widely used for the removal of selected ions from water streams. Within oil & gas, one application is boiler feedwater treatment to remove hardness, i.e. calcium and magnesium. Weak acid cation (WAC) resins are typically used and advances in material science, polymer chemistry and manufacturing methods have resulted in new resins being introduced to the market. These new resins can lower operating costs through higher capacity, reduced chemical consumption during regeneration or improved physical properties.In this research, the performance of a WAC resin used for boiler feedwater treatment in oil & gas operations (resin A) was compared with two new commercial resins (resins B & C).The results indicated that resin B had the highest operational capacity in comparison to A & C. During regeneration, resin B was the most efficient with 0.43 meq of calcium and magnesium removed from the feed per meq of HCl consumed during regeneration, slightly higher than resins A & C at 0.38 and 0.30 meq/meq respectively. All three resins demonstrated preferential affinity for calcium over magnesium. As breakthrough approached, previously adsorbed magnesium ions were released back to the water resulting in a spike in effluent magnesium that was ≈3× higher than in the feed stream. In full-scale systems, breakthrough can be determined by measuring only the effluent magnesium concentration which can be more sensitive parameter than total hardness and/or calcium.

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Regeneration of pilot-scale ion exchange columns for hexavalent chromium removal

Cited by 112 publications

References 19 publications

Ceria‐Zirconia/Zeolite Bifunctional Catalyst for Highly Selective Conversion of Syngas into Aromatics

Ceria‐Zirconia/Zeolite Bifunctional Catalyst for Highly Selective Conversion of Syngas into Aromatics

Stannous chloride reduction–filtration for hexavalent and total chromium removal from groundwater

Evaluation of new ion exchange resins for hardness removal from boiler feedwater

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