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Pedro J. J. Alvarez

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.


Papers
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TL;DR: A 16S rRNA biomarker was developed to estimate the concentration of putative benzene degraders in a methanogenic consortium that has been enriched on benzene for several years and the utility of this primers and probe set to assess anaerobic benzene degradation potential was demonstrated.
Abstract: Summary Benzene is a common groundwater pollutant that is often recalcitrant under the anaerobic conditions that prevail at hydrocarbon-contaminated aquifers. Thus, determining the potential for anaerobic benzene degradation is important to assess the feasibility of intrinsic bioremediation. In this work we developed a 16S rRNA biomarker to estimate the concentration of putative benzene degraders in a methanogenic consortium that has been enriched on benzene for several years. Primers were designed based on phylogenetic information from this consortium. The primers and probe were obtained by sequencing the dominant denaturing gradient gel electrophoresis band of this consortium, which corresponded to Desulfobacterium sp. clone OR-M2. No hybridization was observed with DNA samples from negative controls (i.e. toluene-degrading and dehalorespiring methanogenic consortia that do not degrade benzene). Samples from an anaerobic aquifer column that was bioaugmented with this benzene-degrading consortium showed a strong correlation between benzene degradation activity and the concentration of the target organism. Although our data do not prove that Desulfobacterium sp. is a benzene degrader, its enrichment as a result of benzene consumption and its correlation to anaerobic benzene degradation activity suggest that it either initiates benzene degradation or is a critical (commensal) partner. Therefore, the utility of this primers and probe set to assess anaerobic benzene degradation potential was demonstrated. This is the first report of the use of real-time quantitative PCR for forensic analysis of anaerobic benzene degradation. Whether this biomarker will be adequately selective and broadly applicable to assess benzene degradation potential under

54 citations

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TL;DR: In this paper, a dual-functional reducing and stabilizing agent was used to form gold nanoparticles (AuNPs) of controlled size based on temperature, achieving an average size of ∼11nm at room temperature and 7nm at 80°C.
Abstract: We demonstrate sodium rhodizonate as a novel dual-functional reducing and stabilizing agent to form gold nanoparticles (AuNPs) of controlled size based on temperature. At room temperature (ca. 23 °C), the method generates AuNPs with an average size of ∼11 nm, whereas at 80 °C, it forms AuNPs with an average size of ∼7 nm. The rhodizonate-stabilized AuNPs readily bind to cellulose fibers (CF) while maintaining a high catalytic activity. The catalytic activity of the CF-supported AuNPs nanocomposites is demonstrated by the reduction of 4-nitrophenol (4-NP) and organic dyes such as methyl orange (MO), methylene blue (MB) in water. A glass column-based continuous catalytic reduction and its recyclability is also demonstrated for practical applications.

53 citations

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TL;DR: Quantitative polymerase chain reaction measurements showed that gene markers corresponding to putative pathogenic bacteria were more abundant in indoor floodwater than in street floodwater and bayou water, and higher abundances of 16S rRNA and sul1 genes were also found.
Abstract: Urban flooding can dramatically affect the local microbial landscape and increase the risk of waterborne infection in flooded areas. Hurricane Harvey, the most destructive hurricane since Katrina in 2005, damaged more than 100000 homes in Houston and flooded numerous wastewater treatment plants. Here we surveyed microbial communities in floodwater inside and outside residences, bayou water, and residual bayou sediment collected immediately postflood. Levels of Escherichia coli, a fecal indicator organism, were elevated in bayou water samples as compared to historical levels, as were relative abundances of key indicator genes of anthropogenic sources of antibiotic resistance (sul1/16S rRNA and intI1/16S rRNA) based on 6 month postflood monitoring. Quantitative polymerase chain reaction measurements showed that gene markers corresponding to putative pathogenic bacteria were more abundant in indoor floodwater than in street floodwater and bayou water. Higher abundances of 16S rRNA and sul1 genes were also ob...

53 citations

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TL;DR: Large granules in R1 with intact extracellular polymeric substances (EPS) outer layer structure entrapped hydroxyapatite at center, which formed a core structure and further enhanced the stability of aerobic granules.

53 citations

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TL;DR: The phage life cycle is considered and its implications for bacterial control are considered, and the biochemical basis of such potential application niches in the water supply and reuse cycle is elaborate.
Abstract: ConspectusWater security to protect human lives and support sustainable development is one of the greatest global challenges of this century. While a myriad of water pollutants can impact public health, the greatest threat arises from pathogenic bacteria that can be harbored in different components of water treatment, distribution, and reuse systems. Bacterial biofilms can also promote water infrastructure corrosion and biofouling, which substantially increase the cost and complexity of many critical operations.Conventional disinfection and microbial control approaches are often insufficient to keep up with the increasing complexity and renewed relevance of this pressing challenge. For example, common disinfectants cannot easily penetrate and eradicate biofilms, and are also relatively ineffective against resistant microorganisms. The use of chemical disinfectants is also curtailed by regulations aimed at minimizing the formation of harmful disinfection byproducts. Furthermore, disinfectants cannot be use...

51 citations


Cited by
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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

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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

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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

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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

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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