The role of intraparticle diffusion path length during electro-assisted regeneration of ion exchange resins: Implications for selective adsorbent design and reverse osmosis pretreatment

Selective aqueous ammonia sensors using electrochemical stripping and capacitive detection

“…In remote areas, the small volume of ammonium sulfate could either be recovered as a product or discharged with the alkaline cathode chamber before discharge. As we have shown previously, sulfuric acid can be a major contributor to life‐cycle energy, emissions, and costs for treatment processes that recover nitrogen from wastewaters; 44–46 thus, reducing sulfuric acid replacement frequency can also influence the cost and environmental impacts of nitrogen monitoring via ECS‐CD. Although we have focused on sulfuric acid here, several other absorbents, including hydrochloric acid, acetic acid, and activated carbon particles, have been demonstrated for ammonia membrane stripping 47,48 .…”

Use of a Novel Bio-Nano-IX Process to Remove SeO42– or Se(VI) from Contaminated Water in the Presence of Competing Sulfate (SO42–)

“…Integrating such an approach to reduce selenate to selenite in the two-step bio-nano-ix process will very likely decrease the size or footprint of the entire process and, thus, be economically attractive. A recent study has shown that HAIX-NanoFe may also be regenerated efficiently through electrolysis of NaCl, thus avoiding the use of transport of alkali and acid to the site. , The bio-nano-ix configuration is simple and operationally robust; for lengthy runs lasting several months, occasional fluctuations in the flow rate and influent selenium concentration had no noticeable effect on the efficiency of selenium removal. It is expected that the bio-nano-ix process will stimulate field-scale trials for further validation and development of appropriate design algorithms.…”

CO2 Utilization for Water Treatment: Ion Exchange Nitrate Removal Driven by CO2 without Producing Spent Brine Regenerant

“…This effect of the intraparticle diffusion path length on regeneration kinetics has also been illustrated using a more elaborate approach by the Nernst−Planck equation previously. 40 The intraparticle diffusion path length and regeneration kinetics affects regeneration efficiency more with mild acid regenerants like carbonic acid in CO 2 regeneration than with conventional regenerants, because the counterion diffusion was much slower with a lower concentration gradient provided by the mild acid compared to conventional high concentration regenerants. To demonstrate the improved regeneration efficiency with short intraparticle diffusion path length (fast regeneration kinetics) using the shallow shell strategy, we tested both WAC and SSWAC under identical CO 2 regeneration conditions.…”

“…Particularly, CO 2 utilization incentivizes CO 2 capture and has shown great potentials in the water sector for water and wastewater treatment; however, CO 2 utilization in the water sector still remains in its infancy due to the lack of deployable technologies . Meanwhile, IX as a selective separation technology has been increasingly applied for various decontamination applications due to the improving resin selectivity toward species like arsenic, fluoride, nitrate, phosphate, ammonium, and organics (e.g., PFASs). − Besides water decontamination, IX desalination also has become progressively viable for treating and reusing nontraditional water sources because of their much lower salinities (e.g., <3000 mg/L TDS) compared to seawaters. − In addition, the increasing demand for selectivity during other processes such as membrane desalination further expands IX applications such as for membrane antiscaling pretreatments by selectively removing scaling ions. − These broad IX implementations promise that once CO 2 regeneration is further improved and rapidly adopted, the CO 2 -driven IX platform can readily facilitate CO 2 utilization in the water sector for water decontamination and desalination, while tackling the brine disposal challenges.…”