Monrovia, CA, United States
Monrovia, CA, United States
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Chen D.P.,Korea Advanced Institute of Science and Technology | Yu C.,AquaNano LLC | Yu C.,California Institute of Technology | Chang C.-Y.,AquaNano LLC | And 7 more authors.
Environmental Science and Technology | Year: 2012

Perchlorate (ClO4 -) is a persistent contaminant found in drinking groundwater sources in the United States. Ion exchange (IX) with selective and disposable resins based on cross-linked styrene divinylbenzene (STY-DVB) beads is currently the most commonly utilized process for removing low concentrations of ClO4 - (10-100 ppb) from contaminated drinking water sources. However, due to the low exchange capacity of perchlorate-selective STY-DVB resins (∼0.5-0.8 eq/L), the overall cost becomes prohibitive when treating groundwater with higher concentration of ClO4 - (e.g., 100-1000 ppb). In this article, we describe a new perchlorate-selective resin with high exchange capacity. This new resin was prepared by alkylation of branched polyethyleneimine (PEI) beads obtained from an inverse suspension polymerization process. Batch and column studies show that our new PEI resin with mixed hexyl/ethyl quaternary ammonium chloride exchange sites can selectively extract trace amounts of ClO4 - from a makeup groundwater (to below detection limit) in the presence of competing ions. In addition, this resin has a strong-base exchange capacity of 1.4 eq/L, which is 1.75-2.33 times larger than those of commercial perchlorate-selective STY-DVB resins. The overall results of our studies suggest that branched PEI beads provide versatile and promising building blocks for the preparation of perchlorate-selective resins with high exchange capacity. © 2012 American Chemical Society.


Mishra H.,California Institute of Technology | Yu C.,AquaNano LLC | Yu C.,California Institute of Technology | Chen D.P.,Korea Advanced Institute of Science and Technology | And 6 more authors.
Environmental Science and Technology | Year: 2012

Extraction of boron from aqueous solutions using selective resins is important in a variety of applications including desalination, ultrapure water production, and nuclear power generation. Today's commercial boron-selective resins are exclusively prepared by functionalization of styrene-divinylbenzene (STY-DVB) beads with N-methylglucamine to produce resins with boron-chelating groups. However, such boron-selective resins have a limited binding capacity with a maximum free base content of 0.7 eq/L, which corresponds to a sorption capacity of 1.16 ± 0.03 mMol/g in aqueous solutions with equilibrium boron concentration of ∼70 mM. In this article, we describe the synthesis and characterization of a new resin that can selectively extract boron from aqueous solutions. We show that branched polyethylenimine (PEI) beads obtained from an inverse suspension process can be reacted with glucono-1,5-d-lactone to afford a resin consisting of spherical beads with high density of boron-chelating groups. This resin has a sorption capacity of 1.93 ± 0.04 mMol/g in aqueous solution with equilibrium boron concentration of ∼70 mM, which is 66% percent larger than that of standard commercial STY-DVB resins. Our new boron-selective resin also shows excellent regeneration efficiency using a standard acid wash with a 1.0 M HCl solution followed by neutralization with a 0.1 M NaOH solution. © 2012 American Chemical Society.


Patent
AquaNano LLC | Date: 2014-09-17

The present disclosure is directed to polymeric beads, methods of making the beads, and methods of using the beads as high-capacity anion exchange materials. In particular, the disclosure provides polymeric beads comprising a cross-linked polyamine and having a crush strength of about 250 g/bead or more. Preferably, the beads are substantially spherical. Also disclosed are polymeric beads comprising a cross-linked polyamine that has a substantial number of both strong base sites and weak base sites. Methods of using the polymeric beads in various industrial applications, such as groundwater remediation, radio waste management, municipal wastewater management, demineralization, toxin removal, mining, food refinery, research, agriculture, and the like, are also disclosed herein.


Trademark
AquaNano LLC | Date: 2013-01-10

Chemicals for industrial purposes; chemicals for use in industry; and chemicals for scientific purposes.


Grant
Agency: Environmental Protection Agency | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 100.00K | Year: 2014

Identification and Significance of the Opportunity. Perchlorate is a water-soluble anion that has emerged as a major contaminant of drinking groundwater sources in the United States. Various states have set public health goals for acceptable perchlorate levels in drinking water. For example, the State of California established a maximum concentration limit (MCL) of 6 ppb (mg/L) in October 2007 and proposed in January 2011 to reduce the MCL for ClO4• in drinking water from 6 ppb to 1 ppb. Single-pass ion exchange (IX) with selective and disposable resins is currently the best available technology for treating drinking groundwater sources with ClO4• concentration less than 100 ppb. However, commercial perchlorate-selective resins (PSRs) have a relatively low exchange/operational capacity with a strong-base capacity (SBC) ranging from 0.65 eq/L to 0.85 eq/L. As result, the overall cost becomes prohibitive when treating drinking groundwater sources with higher perchlorate concentrations (e.g., 100 ppb to 1000 ppb) or containing large concentrations of competing anions, such as nitrate. Next Generation of High-Capacity PSRs. AquaNano has developed a new PSR with high exchange capacity—an SBC of 1.50 eq/L—that meets the specifications for commercial PSRs in crush strength, particle-size distribution and bead integrity. Preliminary experiments show that the column operational capacity of AquaNano’s PSR is 1.70 times higher than that of a commercial PSR with a reported SBC of 0.85 eq/L for perchlorate extraction from a makeup groundwater containing an effluent ClO4• concentration of 10 mg/L. Project Objectives and Research Plan. In Phase I of this EPA SBIR proposal, we will explore the commercialization of this new PSR as disposable media for single-pass IX systems. This Phase I SBIR EPA proposal has three specific objectives: Scale up and optimize our resin-preparation procedures to consistently produce 5- to 10-Kg batches of a commercial-grade PSR with high SBC (~1.50 eq/L). Verify and validate the performance of these new high-capacity PSRs through column field tests at two groundwater sites in California. Collect the data required to develop a roadmap for a Phase II SBIR proposal to accelerate the commercialization of this new PSR. Expected Results and Commercial Potential. We expect the successful completion of the Phase I project to provide the data needed to develop a Phase II SBIR proposal to validate AquaNano’s PSR as high-capacity media for perchlorate removal from drinking groundwater using single-pass IX treatment processes.


Trademark
AquaNano LLC | Date: 2012-03-13

Chemicals for industrial purposes; chemicals for use in industry; and chemicals for scientific purposes.

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