Stanford Advisors


Patents


  • Arup K. Sengupta, Hang Dong, Michael German, Chelsey Shepsko. "United States Patent US10472261B2 Contaminants removal with simultaneous desalination using carbon dioxide regenerated hybrid ion exchanger nanomaterials", Lehigh University, Nov 12, 2019

All Publications


  • Electro-assisted regeneration of pH-sensitive ion exchangers for sustainable phosphate removal and recovery. Water research Dong, H., Wei, L., Tarpeh, W. A. 2020; 184: 116167

    Abstract

    Removal and recovery of phosphate from wastewater can minimize deleterious environmental impacts and supplement fertilizer supply. Hybrid anion exchangers (HAIX, with doped ferric oxide nanoparticles (FeOnp)) can remove phosphate from complex wastewaters and recover concentrated phosphate solutions. In this study, we integrate HAIX with a weak acid cation exchanger (WAC) to enrich phosphate and calcium in mild regenerants and precipitate both elements for recovery. We demonstrated an electro-assisted regeneration approach to avoid strong acid and base input. Based on demonstrated pH sensitivities of both materials, electrochemically produced mild electrolytes (pH 3 and pH 11), which are 100-1000 times less concentrated than typical regenerants, preserved 80% WAC and 50% HAIX capacities over five batch adsorption-regeneration cycles. FeOnp in HAIX facilitated regeneration due to pH sensitivity and their likely distribution on the resin particle surface, which reduced intraparticle diffusion path length. In column tests, repeatable phosphate removal (> 95%) from synthetic wastewater (3mg P/L) was achieved with 20kWh/kg P specific energy consumption. After removal, a similar 50% HAIX regeneration efficiency as batch experiments was achieved. In spent regenerant, more than 95% phosphorus was recovered as hydroxyapatite. This novel approach enhances ion exchange by minimizing chemical inputs.

    View details for DOI 10.1016/j.watres.2020.116167

    View details for PubMedID 32682079

  • Multifunctional ion exchange pretreatment driven by carbon dioxide for enhancing reverse osmosis recovery during impaired water reuse DESALINATION Dong, H., German, M., Tian, L., SenGupta, A. K. 2020; 485
  • Field validation of self-regenerating reversible ion exchange-membrane (RIX-M) process to prevent sulfate and silica fouling DESALINATION German, M. S., Dong, H., Schevets, A., Smith, R. C., SenGupta, A. K. 2019; 469
  • Hybrid Ion Exchange Desalination (HIX-Desal) of Impaired Brackish Water Using Pressurized Carbon Dioxide (CO2) as the Source of Energy and Regenerant ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS Dong, H., Shepsko, C. S., German, T., SenGupta, A. K. 2018; 5 (11): 701–6
  • Field validation of multifunctional ion exchange process for reverse osmosis pretreatment and phosphate recovery during impaired water reuse JOURNAL OF WATER PROCESS ENGINEERING Dong, H., Lin, T., SenGupta, A. K. 2020; 36
  • Efficient removal of triclosan via peroxymonosulfate activated by a ppb level dosage of Co(II) in water: Reaction kinetics, mechanisms and detoxification. Ecotoxicology and environmental safety Peng, J., Zhang, C., Zhang, Y., Shao, S., Wang, P., Liu, G., Dong, H., Liu, D., Shi, J., Cao, Z., Liu, H., Gao, S. 2020; 198: 110676

    Abstract

    Triclosan (TCS), an extensively used broad-spectrum antimicrobial agent, has raised significant environmental concerns regarding its widespread occurrence in waters. In this study, the removal of TCS in aqueous solution via peroxymonosulfate (PMS) activated by an extremely low-level Co2+ (0.02muM) was systematically investigated. During preliminary test, TCS (10muM) was totally degraded in 30min by using 0.1muM Co2+ and 40muM PMS at pH 7.0 with a degradation rate constant of 0.1219 min-1. A first-order apparent degradation rate of TCS was found with respect to the PMS concentrations. At extremely low dosage of Co2+ (0.02muM), the presence of NO3-, HCO3-, PLFA, and SRHA within test concentrations significantly inhibited TCS removal, while a dual effect of Cl- on the degradation rate of TCS was observed. The quenching experiments verified that SO4- was the dominant reactive oxygen species (ROS) rather than OH. Six major intermediates were identified using TOF-LC-MS, based on which we proposed three associated reaction pathways including hydroxylation, ether bond breakage, and dechlorination. Toxicity predictions by ECOSAR software exhibited aquatic toxicity reduction of TCS after Co2+/PMS treatment. We outlook these findings to advance the feasibility of organic contaminants removal via Co2+/PMS system with Co2+ at extremely low levels.

    View details for DOI 10.1016/j.ecoenv.2020.110676

    View details for PubMedID 32361496

  • Hybrid nitrate selective resin (NSR-NanoZr) for simultaneous selective removal of nitrate and phosphate (or fluoride) from impaired water sources Journal of Environmental Chemical Engineering Dong, H., Shepsko, C. S., German, M., SenGupta, A. K. 2020; 8 (4)
  • Treated Municipal Wastewater Reuse: A Holistic Approach Using Hybrid Ion Exchange (HIX) with Concurrent Nutrient Recovery and CO2 Sequestration ACS SUSTAINABLE CHEMISTRY & ENGINEERING Shepsko, C. S., Dong, H., SenGupta, A. K. 2019; 7 (10): 9671–79