IRG 3 Intellectual Focus:
The projects envisioned by the IRG 3 are addressing challenges in the areas of (1) drinking and groundwater treatments and (2) removal/storage/sequestration of light gas contaminants. Specifically, the IRG will apply nanoscale materials to the removal of pharmaceutical and personal care products (PPCPs) and other organic contaminants from potable water, the removal of metals from water, the recovery of water from human waste in spacecraft, and the removal and conversion of CO2.
IFN Faculty Participants (13):
C. Cabrera,+ N. Cardona-Martinez,* M. Curet-Arana,* K. Griebenow,+ A.J. Hernandez-Maldonado (IRG3 leader),* S. Hwang,* Y. Ishikawa,+ M. Martínez-Iñesta,* O. Perales,* R. Raptis,+ R. Rios,+ H. Rivera-Betancourt§, F. Roman,* (*Univ. of Puerto Rico at Mayaguez (UPR-M), +Rio Piedras (UPR-RP) and §Inter-American Univ. of Puerto Rico (IAUPR)).
IFN Strategic Partner Collaborators (7):
J. Hogan and M. Flynn, NASA Ames Research Center (ARC); F. Rosario-Ortiz, Univ. of Colorado at Boulder; B. Mariñas, Univ. of Illinois – Urbana Champaign; R. Fu, National High Magnetic Field Laboratory (NHMFL); Bryan Coughlin and James Watkins, University of Massachusetts-Amherst.
Other Partner Collaborators (4):
J. Feliu, University of Alicante; Manos Mavrikakis, U. Wisconsin, Madison; J. Lugo, PR-Water Management Authority; Antonio Diaz, Director Waste Management Authority of Puerto Rico.
IFN Postdocs (5):
Supported by this RII grant:Dr. Fajim Hossain (Hwang and Perales)
Supported by other grants: Dr. Moxin Yu (Hernandez-Maldonado); Dr. Xin-Yi Cao (Raptis); Dr. Ileana Gonzalez-Gonzalez (Cabrera); Dr. Yarylin Cedeño (Perales and Roman)
Dr. Fahim Hossain has been working with Perales and Hwang’s laboratories since January 2012. At present, Dr Hossain is doing research at Perales’ facilities in the size-controlled synthesis of TiO2 nanoparticles. These nanoparticles will be used as antimicrobials as well as photo-catalysts to decompose disinfection byproducts generated in water. The bactericidal and disinfecting capacity of TiO2 will be assessed in bare and polymer-based nancomposites. TiO2 nanoparticles have been treated with an ammine source to induce N-doping. Doped TiO2 nanoparticles exhibited enhanced UV photo-degradation efficiency of MB under similar conditins that bare TiO2. In addition, he has composed a review paper on “Antimicrobial nanomaterials as disinfecting agent” that has been submitted to Journal of Experimental Nanoscience and a manuscript to the Materials Research Society on the synthesis and photo-degradation properties of N-doped TiO2. The manuscript is still under review.
All the postdoctoral fellows are required to participate in the mentoring activities delineated in the proposal and attend IRG3 and general IFN meetings as well as to prepare presentations whenever required. The IFN Task Force will continue to evaluate the progress of their research work and dissemination status throughout the year.
IFN Researchers’ Graduate Students (23):
Wilman Cabrera, Omar Garcia, Jose Primera* (Hernandez-Maldonado); Logesh Mathivathanan,* Kaige Shi, Tahereh Mousavinejad (Raptis);Isomar Latorre* (Hwang): Yohaselly Santiago (Curet-Arana); Myrna Torres, Melina Perez, Angelica Torres, Rebeca Caban (Perales); Diana Sanchez, Jose Lopez and Tatiana Luna(Roman y Perales); Jessica Mendez (Griebenow); Lisandra Arroyo, Lisandro Cunci,* Jose Fonseca, Yaritza Hernandez, Eduardo Nicolao, Carlos Poventud (Cabrera); Oscar Oyola Rivera (Cardona-Martínez); (*Recipients of the IFN PhD Fellowships. The remaining students were supported through other grants).
Year 3 Research Accomplishments for the IRG:
Hernandez-Maldonado, Hwang, Perales, Roman, Cabrera and Rivera-Betancourt have been developing new nanomaterials for water remediation. Complexation nanoporous adsorbents based on metal-organic intercalated pillared clays and zeolites were prepared and characterized in the laboratory facilities of Hernandez-Maldonado. Hwang and Hernández have tested SBA-15 for the simultaneous remediation of Di-(2-ethylhexyl) phthalate (DEHP)- and arsenic- containing water. Highest DEHP removal efficiency per unit SBA-15 mass was observed at 77% and 50% for DEHP alone and DEHP-arsenic mixture, respectively, with 3 mg SBA-15 and 10 mM H2O2. Optimum DEHP reduction was found at 2.6 mM Fe, 17.9 mg SBA-15 and 2.7 mg/L As(III) for adsorption and 0.25 mM Fe, 20.5 mg SBA-15, 1.4 mg/L As(III) and 15 mM H2O2 for Fenton regeneration according to Response Surface Methodology.
Perales, Cedeño and Roman have identified the suitable conditions to extract Zn from waste tire crumb rubber. Zn bearing solutions were used to assess their toxicity to alfalfa plants. The optimum leaching conditions at room temperature were determined. Dr. Laura Lopez, a collaborator from Chemistry Department-UPRM, confirmed that alfalfa plants can uptake Zn species as nutrients. Ongoing works are focused on the optimization of the Zn removal from the waste tire and evaluate the use of Alfalfa rich in Zn ad potential nutraceutical compound. Perales and Cedeño have synthesized nanosize MgO and evaluated its bactericidal capacity in presence of E. Coli. Preliminary results are encouraging and suggested nanocrystalline MgO can fully inhibit the growth of the bacteria at suitable concentrations. Perales, and Fahim have synthesized TiO2 NPs via a modified aqueous processing route using HNO3 as a catalyst and polyvinylpyrrolidone as particle size controller and a dispersing agent. The NPs surface was treated by using Ethylenediamine (EDA) as a source for amine species. The photocatalytic activity of TiO2 NPs was assessed by irradiating an aqueous solution of using Methylene blue (MB) dye containing different amounts of the NPs. XRD analyses evidenced the formation of two phases of crystalline TiO2 with an average crystallite size estimated at 15.3 nm. Bare and amine-treated TiO2 NPs exhibited significant activity under UV light illumination (365 nm). Bare NPs exhibited a dye photo degradation capability of about 89.0-92.31% with particle concentration of 1 g/l while amine-treated NPs reported 66.18% dye photo degradation capability with particle concentration of 0.5 g/l.
Perales and Roman also used Ca-Fe(III) alginate beads as a green adsorbent for the removal of inorganic arsenic oxyanions from aqueous solutions. The carboxyl groups present in the Ca-alginate structure are responsible for the binding of divalent cations. The insertion of iron as a dispersed colloidal ferric hydroxide enhanced the adsorption efficiency toward arsenic. The adsorption was fitted by the Langmuir and the Freundlich models, the first being more suitable. The Langmuir parameter q, which indicates the maximum uptake capacity of the sorbent, was 0.364 (mg/g) for As(V) and 0.117 (mg/g) for As(III). These results suggested that the removal mechanism for arsenic species is adsorption onto the iron in the alginate bead surface. Ca-Fe(III) alginate beads could be used as a green alternative to remove trace levels of arsenic oxyanions. Roman and Perales also developed a method for the speciation of arsenic oxyanions mixtures using a liquid chromatography coupled with inductively coupled plasma mass spectrometer (LC-ICPMS) technique. The speciation was carried out during adsorption experiments using dried sludge as adsorbent. The As speciation results demonstrated a low limit of detection (LOD) of 5.26 ppb for arsenite and of 9.85 ppb for arsenate species. Arsenate species was removed faster compared to arsenite species when both are present as mixtures. The data from competitive adsorption tests suggested that the removal mechanism for arsenic species is due to the formation of an outer sphere complex such as electrostatic or Van der Waals attractions. The results show the capability of the dried sludge as a green alternative to remove trace levels of both arsenic oxyanions from contaminated or wastewaters. Also, the developed speciation protocol allowed a better understanding of the adsorption mechanism of arsenic species by Fe-rich sludge.
Cabrera, Rivera-Betancourt in collaboration with Flynn, Coughlin, and Feliu have workedto advance the interface of an urea electrochemical bioreactor for a urine purification and the forward osmosis/reverse osmosis. The goal is to have a combined energy source and waste recovery in water recycling activities. In fact, down-select of the Electrochemical Ammonia Removal System (EAR) was performed. This includes EAR size, power and environmental requirements, pressure analysis, operational and regeneration procedures. During summer 2013, the EAR will be integrated with the Forward Osmosis Secondary Treatment system (FOST) at NASE ARC.The combination of the EAR and FOST will decrease the amount of power and resupplies that are usually needed in long-term space missions. During this reporting period the group worked on the following: (1) the effect of catalyst ink formulation on alkaline fuel cell performance, and (2) the regeneration of the ammonia full cell (AFC). The catalyst ink composition for alkaline fuel cells was elucidated and this included factors such as the amount of ionomer, type and amount of solvent. However, results showed that the reproducibility of the MEA preparation remains one of the main obstacles on this project. On the other hand, during optimization of the ammonia fuel cell MEA it was found that the fuel cell performance decays significantly after 6-8 hours of operation. AFC regeneration process optimization lead us to recovery the original performance of the fuel cell.
Hernandez-Maldonado, Curet-Arana, Raptis and Hogan have been developing nanoporous adsorbents for CO2 removal and storage. Hernandez-Maldonado and his group have prepared nanoporous Cu2(pzdc)2L [L= dipyridyl-based ligands] coordination polymers for efficient CO2storage and sustained delivery. These materials were tested for sustained delivery of CO2 at fixed effluent flow rates in collaboration with Hogan (NASA ARC). Curet performed density-functional theory (DFT) studies to elucidate the interaction between CO2 and the structure of these coordination polymers and explain the hysteretic adsorption-desorption process observed at moderate pressure. Raptis and Hernandez-Maldonado have developed metal organic framework adsorbents sorbents for the selective and high capacity gas separations for space-related missions. The Raptis group has been systematically modifying the peripheral substituents of [Cu2+-pyrazolato]3 MOFs in order to elucidate trends in their CO2-sorption properties. The new materials involve rigid and flexible bipyridyl linkers, which allow the control of lattice interpenetration.
Status of Major Equipment Acquisition Related to IRG3:
A PHI VersaProbe II XPS/ESCA was acquired during Y2 and it is the first instrument if it’s kind in the University of Puerto Rico – Mayaguez. UPRM provided substantial support for the refurbishing of the lab facilities that now how the new VersaProble II system. The lab was fitted with a dedicated electrical grid system, including a 200-230 VAC ± 5 %, single-phase uninterrupted power supply (UPS) system to provide both power conditioning and support in the event of a power outage. In addition, the lab houses a high purity grade air delivery system that provides support for the operation of the XPS pneumatic valve system.
Although the installation of the instrument was also completed during Y2, validation of the operation of the instrument was completed in Febuary 2013 (all of these activities were coordinated by Hernandez-Maldonado). This delay was due to unexpected problems with the instrument X-ray source and several electronic components. The unit is now operational and we plan to report later (Y4) about the research initiatives, dissemination activities and human resources impacted by this acquisition.
Year 3 Testbeds Development and Collaborations with IFN Partners:
Two graduate students of Hernandez and Cabrera spent 10 weeks in NASA Ames Research Center (ARC) working with Hogan and Flynn to test preliminary test bed units to study CO2 storage and delivery systems and a urea forward osmosis/bio-electrochemical hybrid system (FOBE) for water reclamation and resource recovery at NASA setup.
Relevance to Y2-Y3 Strategic Plans:The development of the UPR CO2 removal testbed remains halted due to the unavailability of funding. The development of the Y3 water remediation testbed was halted for the same reasons.