Author
Pedro J. J. Alvarez
Other affiliations: University of Minnesota, University of Michigan, Universidade Federal de Santa Catarina ...read more
Bio: Pedro J. J. Alvarez is an academic researcher from Rice University. The author has contributed to research in topics: Bioremediation & Medicine. The author has an hindex of 89, co-authored 378 publications receiving 34837 citations. Previous affiliations of Pedro J. J. Alvarez include University of Minnesota & University of Michigan.
Topics: Bioremediation, Medicine, Chemistry, Adsorption, Bioaugmentation
Papers published on a yearly basis
Papers
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TL;DR: In this article, X-ray absorption spectroscopy on carbon-supported Pd/Au NPs was conducted to obtain information about the local atomic environment (i.e., oxidation states, coordination numbers, and bond distances).
60 citations
TL;DR: The results highlight the importance of environment-induced changes in nC₆₀ surface chemistry in its fate and transport in aquatic environments.
Abstract: Nanoparticle transport in natural settings is complex due to interactions with the surrounding environment. In this study, the impact of UVA irradiation and humic acid (HA) on deposition of aqueous fullerene nanoparticles (nC60) on a silica surface as a surrogate for natural sediments was studied using packed column experiments and quartz crystal microbalance with dissipation monitoring under various solution conditions. Surface oxidation of nC60 induced by UVA irradiation greatly retarded its deposition due to the increased negative surface charge and hydrophilicity. Dissolved HA, once adsorbed onto the nC60 surface, also hindered its deposition mainly through steric hindrance forces. The extent of this effect depended on the properties and the amount of HA adsorbed, which is a function of ionic strength and HA concentration. HA has limited adsorption on UVA-irradiated nC60 and is expected to play a less important role in its stability. HA immobilized onto the silica surface had a variable effect on nC60 deposition, depending on the complex interplay of Derjaguin−Landau−Verwey−Overbeek (DLVO) and non-DLVO interactions such as electrostatic interaction, steric hindrance, and hydrogen bonding as well as HA molecular conformation. These results highlight the importance of environment-induced changes in nC60 surface chemistry in its fate and transport in aquatic environments.
59 citations
TL;DR: It is shown that mesopores facilitate the formation of large vacancies to counterbalance thermodynamic instability caused by incompletely coordinated Bi and O atoms along the mesopore perimeters, which significantly enhances photocatalytic activity.
Abstract: Vacancy control can significantly enhance the performance of photocatalytic semiconductors for water purification. However, little is known about the mechanisms and approaches that could generate stable large vacancies. Here, we report a new mechanism to induce vacancy formation on nanocrystals for enhanced photocatalytic activity: the introduction of mesopores. We synthesized two nanosheet-assembled hierarchical 3D BiOCl mesoporous nanostructures with similar morphology and exposed facets but different nanosheet thickness. Positron annihilation analysis detected unprecedentedly large VBi‴VO••VBi‴VO••VBi‴ vacancy associates (as well as VBi‴VO••VBi‴) on BiOCl assembled from 3–6 nm nanosheets but only VBi‴VO••VBi‴ vacancy associates on BiOCl assembled from thicker (10–20 nm) nanosheets. Comparison of vacancy properties with 2D ultrathin 2.7 nm nanosheets (with VBi‴VO••VBi‴ and VBi‴) indicates that nanosheet thinness alone cannot explain the formation of such large atom vacancies. On the basis of density fun...
58 citations
TL;DR: An ultra-high surface area porous activated carbon derived from low cost asphalt (AS) was synthesized and investigated for removal of bisphenol A (BPA), a common endocrine disrupting chemical (EDC) in wastewater and natural waters.
56 citations
TL;DR: In this article, a microbial fuel cell (MFC) fed with produced water (Barnett Shale), which produced power (47mW/m2) and accomplished a COD removal efficiency of 68% (influent COD 10,520-±-1340-mg/L).
56 citations
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TL;DR: It is anticipated that this review can stimulate a new research doorway to facilitate the next generation of g-C3N4-based photocatalysts with ameliorated performances by harnessing the outstanding structural, electronic, and optical properties for the development of a sustainable future without environmental detriment.
Abstract: As a fascinating conjugated polymer, graphitic carbon nitride (g-C3N4) has become a new research hotspot and drawn broad interdisciplinary attention as a metal-free and visible-light-responsive photocatalyst in the arena of solar energy conversion and environmental remediation. This is due to its appealing electronic band structure, high physicochemical stability, and “earth-abundant” nature. This critical review summarizes a panorama of the latest progress related to the design and construction of pristine g-C3N4 and g-C3N4-based nanocomposites, including (1) nanoarchitecture design of bare g-C3N4, such as hard and soft templating approaches, supramolecular preorganization assembly, exfoliation, and template-free synthesis routes, (2) functionalization of g-C3N4 at an atomic level (elemental doping) and molecular level (copolymerization), and (3) modification of g-C3N4 with well-matched energy levels of another semiconductor or a metal as a cocatalyst to form heterojunction nanostructures. The constructi...
5,054 citations
TL;DR: The mechanisms of generation and potential impacts of microplastics in the ocean environment are discussed, and the increasing levels of plastic pollution of the oceans are understood, it is important to better understand the impact of microPlastic in the Ocean food web.
4,706 citations
TL;DR: In this paper, the complex mechanisms of Fenton and Fenton-like reactions and the important factors influencing these reactions, from both a fundamental and practical perspective, in applications to water and soil treatment, are discussed.
Abstract: Fenton chemistry encompasses reactions of hydrogen peroxide in the presence of iron to generate highly reactive species such as the hydroxyl radical and possibly others. In this review, the complex mechanisms of Fenton and Fenton-like reactions and the important factors influencing these reactions, from both a fundamental and practical perspective, in applications to water and soil treatment, are discussed. The review covers modified versions including the photoassisted Fenton reaction, use of chelated iron, electro-Fenton reactions, and Fenton reactions using heterogeneous catalysts. Sections are devoted to nonclassical pathways, by-products, kinetics and process modeling, experimental design methodology, soil and aquifer treatment, use of Fenton in combination with other advanced oxidation processes or biodegradation, economic comparison with other advanced oxidation processes, and case studies.
3,218 citations
TL;DR: Due to complexity of soil-water system in nature, the effectiveness of biochars on remediation of various organic/inorganic contaminants is still uncertain.
3,163 citations
TL;DR: The technical feasibility of various low-cost adsorbents for heavy metal removal from contaminated water has been reviewed and it is evident from the literature survey of about 100 papers that low- cost adsorbent have demonstrated outstanding removal capabilities for certain metal ions as compared to activated carbon.
3,072 citations