The Experts below are selected from a list of 1065 Experts worldwide ranked by ideXlab platform

Xiangning Huang - One of the best experts on this subject based on the ideXlab platform.

  • Towards A Better Understanding of Contaminant Fate in Plastic Plumbing Systems and Their Remediation
    2019
    Co-Authors: Xiangning Huang
    Abstract:

    This dissertation focused on better understanding the fundamental processes that control organic and inorganic contaminant interaction with plastic Plumbing Pipes. Plastic Pipes are increasingly being installed for drinking water Plumbing, but their role in affecting drinking water quality has received little study. It is well-known that plastic Pipes can sorb and release organic contaminants and be difficult to decontaminate. Several problems were identified in the literature and through discussions with industry: (1) Past guidance issued to communities affected by petroleum contaminated water does not seem to specifically consider plastic Plumbing Pipe remediation, (2) investigators have also identified heavy metals can accumulate on Pipe inner walls, (3) Others have proposed certain heavy metals can catalyze plastic water Pipe degradation, (4) No nondestructive cleaning methods were found for removing metal scales from plastic Pipes. These topics were a basis for studies conducted because lack of information inhibits greater protection of public health, safety, and welfare. This dissertation involved the application of knowledge and techniques from the environmental engineering and science, polymer engineering, and material science disciplines. Chapter 1 focused on the response of copper and plastic Pipes (i.e., chlorinated polyvinylchloride (cPVC), high-density polyethylene (HDPE), crosslinked polyethylene (PEX)) exposed to petroleum contaminated drinking water. Bench-scale results revealed that Pipe rinsing followed by a single 3 day water stagnation period removed target monoaromatic hydrocarbons (MAH) from copper Pipes, but much longer (>15 days) time was required for decontaminating cPVC, HDPC, and PEX Pipes. Benzene, trimethylbenzene and polynuclear aromatic hydrocarbons, some of which are not typically considered in drinking water contamination investigations, were found desorbed into clean drinking water from Pipes. Future Plumbing decontamination guidance should consider the conditions necessary for plastic Pipe remediation. Chapter 2 describes the influence of drinking water conditions on heavy metal contaminant – low density polyethylene (LDPE) pellet surface interactions. Mixed metal drinking water solutions were applied and contained Cu, Fe, Mn, Pb and Zn at 30 µg/L. LDPE was selected as the model polymer because of its prior use for piping in Europe, use in bench-scale studies by others, and similarity to products used for the manufacture of more complex materials in the USA (HDPE, PEX). As expected, metal loadings were about 5 times greater for aged LDPE pellets suspended in solution compared to new LDPE pellets. This difference was attributed to the aged plastic surfaces having oxygen containing functional groups, increased surface area, and enhanced hydrophilicity. Metal loading was lower at pH >9.5 and in the presence of dissolved organic contaminants. The presence of free chlorine and corrosion inhibitor also decreased metal adsorption onto LDPE pellets. These factors likely enabled metal precipitation thereby not allowing metal species to adsorb to LDPE pellets suspended in water. XPS results showed deposited metals (i.e., Cu, Pb, Zn) primarily consisted of hydroxides and oxides. To further understand heavy metal – plastic Pipe interactions, Chapter 3 involved the use of metal and plastic Pipe rigs and exhumed PEX Plumbing Pipes. Exhumed cold and hot water PEX Pipes contained a noticeable amount of heavy metals (i.e., most abundant metals were 2049 mg/m2 Fe, 400 mg/m2 Ca, 438 mg/m2 Zn and 150 mg/m2 P). Metal release and deposition onto PEX Pipe was examined using bench-scale Pipe rigs that contained new PEX Pipe, brass valves, and copper Pipe. Two water matrices (pH 4 and 7.5) and two temperatures (23oC and 55oC) were explored. The pH 4 water often accelerated metal leaching from brass valves, and a greater amount of heavy metals deposited on PEX Pipes at high water pH and temperature (pH 4 and 55oC) conditions. Oxygen containing functional groups were detected on PEX Pipes connected to a brass valve or a brass valve combined copper Pipe, but were not found on PEX Pipe only (controls) samples, indicating that certain configurations may facilitate plastic Pipe degradation. The last chapter describes the ability of a new lignin derived ligand to remove metal deposits from exhumed PEX Plumbing Pipes. When the ligand concentration was ≥ 5mM, more than 95% of sorbed metals (i.e., Cu, Fe, Mn, Pb and Zn) were removed. The ligand favored certain metals over others (Cu > Zn > Fe > Mn > Pb) and heavy metal removal mechanisms were proposed. This dissertation provides insights into the role of plastic Pipes on drinking water quality. As plastic Pipes continue to be installed, it is in the interest of public health, welfare, and safety to understand their role in positively and negatively affecting drinking water safety

  • In-situ cleaning of heavy metal contaminated plastic water Pipes using a biomass derived ligand
    Journal of Environmental Chemical Engineering, 2017
    Co-Authors: Xiangning Huang, M. Abu-omar, Shou Zhao, Andrew J Whelton
    Abstract:

    Lignin derived monomer (2-methoxy-4-propylphenol, Dihydroeugenol, DHE) was used to synthesize a biomass based Plumbing Pipe cleaning agent (DHEL). DHEL's metal deposit removal efficiency for an exhumed plastic drinking water Pipe was examined. The total metal deposited on 3 cm Pipe segments was first characterized and heterogeneous metal loading (μg/dm2) along consecutive Pipe segments was found. Fe was the most abundant metal species detected, followed by Mn, Ca, Zn, Mg, Cu, Pb and Al. Both DHEL metal removal kinetic and performance studies (0.1 to 10 mM) were conducted at room temperature and neutral pH for up to 7 days. Results showed DHEL effectively removed metal deposits from exhumed plastic Pipe surfaces. By the end of the experiment, ≥ 95% of total metal loadings were removed when DHEL dosage was ≥ 5 mM. Both first order and second order kinetic models were used to fit the experimental data. DHEL showed higher favorability for Cu and Zn rather than Fe, Mn, and Pb. DHEL-metal removal mechanisms were proposed as: 1) ligand-promoted minerals dissolution, and 2) ligand-metal complex formation. The biomass derived ligand demonstrated potential as an effective plastic Pipe cleaning agent.

Mark Lange - One of the best experts on this subject based on the ideXlab platform.

  • Suggestions for Low-Cost Equipment for Physical Geography I: Laboratory Equipment
    Journal of Geography, 2002
    Co-Authors: Patrick Pease, Scott A. Lecce, Paul Gates, Mark Lange
    Abstract:

    Abstract Fieldwork and laboratory experiences have always been important components of physical geography education, at universities as well as secondary schools. However, the rising cost of necessary equipment and dwindling education budgets of most universities and secondary schools have placed such experiences in crisis. This is the first of two papers that present lab- and field-based items we have designed and built for student research. The equipment is easy to construct and made from low-cost materials like PVC Plumbing Pipe. Photographs, construction notes, and costs have been included for each of the pieces of equipment, as well as measured schematics for the more complex items.

  • Suggestions for Low-Cost Equipment for Physical Geography II: Field Equipment
    Journal of Geography, 2002
    Co-Authors: Patrick Pease, Scott A. Lecce, Paul Gates, Mark Lange
    Abstract:

    Abstract Fieldwork and laboratory experiences have always been important components of physical geography education, at universities as well as secondary schools. However, the rising cost of necessary equipment and dwindling education budgets of most universities and secondary schools have placed such experiences in crisis. This is the second of two papers that present lab- and field-based items we have designed and built for student research. The equipment is easy to construct and made from low-cost materials like PVC Plumbing Pipe. Photographs, construction notes, and costs have been included for each of the pieces of equipment, as well as measured schematics for the more complex items.

Andrew J Whelton - One of the best experts on this subject based on the ideXlab platform.

  • In-situ cleaning of heavy metal contaminated plastic water Pipes using a biomass derived ligand
    Journal of Environmental Chemical Engineering, 2017
    Co-Authors: Xiangning Huang, M. Abu-omar, Shou Zhao, Andrew J Whelton
    Abstract:

    Lignin derived monomer (2-methoxy-4-propylphenol, Dihydroeugenol, DHE) was used to synthesize a biomass based Plumbing Pipe cleaning agent (DHEL). DHEL's metal deposit removal efficiency for an exhumed plastic drinking water Pipe was examined. The total metal deposited on 3 cm Pipe segments was first characterized and heterogeneous metal loading (μg/dm2) along consecutive Pipe segments was found. Fe was the most abundant metal species detected, followed by Mn, Ca, Zn, Mg, Cu, Pb and Al. Both DHEL metal removal kinetic and performance studies (0.1 to 10 mM) were conducted at room temperature and neutral pH for up to 7 days. Results showed DHEL effectively removed metal deposits from exhumed plastic Pipe surfaces. By the end of the experiment, ≥ 95% of total metal loadings were removed when DHEL dosage was ≥ 5 mM. Both first order and second order kinetic models were used to fit the experimental data. DHEL showed higher favorability for Cu and Zn rather than Fe, Mn, and Pb. DHEL-metal removal mechanisms were proposed as: 1) ligand-promoted minerals dissolution, and 2) ligand-metal complex formation. The biomass derived ligand demonstrated potential as an effective plastic Pipe cleaning agent.

Patrick Pease - One of the best experts on this subject based on the ideXlab platform.

  • Suggestions for Low-Cost Equipment for Physical Geography I: Laboratory Equipment
    Journal of Geography, 2002
    Co-Authors: Patrick Pease, Scott A. Lecce, Paul Gates, Mark Lange
    Abstract:

    Abstract Fieldwork and laboratory experiences have always been important components of physical geography education, at universities as well as secondary schools. However, the rising cost of necessary equipment and dwindling education budgets of most universities and secondary schools have placed such experiences in crisis. This is the first of two papers that present lab- and field-based items we have designed and built for student research. The equipment is easy to construct and made from low-cost materials like PVC Plumbing Pipe. Photographs, construction notes, and costs have been included for each of the pieces of equipment, as well as measured schematics for the more complex items.

  • Suggestions for Low-Cost Equipment for Physical Geography II: Field Equipment
    Journal of Geography, 2002
    Co-Authors: Patrick Pease, Scott A. Lecce, Paul Gates, Mark Lange
    Abstract:

    Abstract Fieldwork and laboratory experiences have always been important components of physical geography education, at universities as well as secondary schools. However, the rising cost of necessary equipment and dwindling education budgets of most universities and secondary schools have placed such experiences in crisis. This is the second of two papers that present lab- and field-based items we have designed and built for student research. The equipment is easy to construct and made from low-cost materials like PVC Plumbing Pipe. Photographs, construction notes, and costs have been included for each of the pieces of equipment, as well as measured schematics for the more complex items.

Muzi Zheng - One of the best experts on this subject based on the ideXlab platform.

  • Fate of free chlorine in drinking water during distribution in premise Plumbing
    Ecotoxicology, 2015
    Co-Authors: Muzi Zheng
    Abstract:

    Free chlorine is a potent oxidizing agent and has been used extensively as a disinfectant in processes including water treatment. The presence of free chlorine residual is essential for the prevention of microbial regrowth in water distribution systems. However, excessive levels of free chlorine can cause adverse health effects. It is a major challenge to maintain appropriate levels of free chlorine residual in premise Plumbing. As the first effort to assessing the fate of chlorine in premise Plumbing using actual premise Plumbing Pipe sections, three piping materials frequently used in premise Plumbing, i.e. copper, galvanized iron, and polyvinyl chloride (PVC), were investigated for their performance in maintaining free chlorine residual. Free chlorine decay was shown to follow first-order kinetics for all three Pipe materials tested. The most rapid chlorine decay was observed in copper Pipes, suggesting the need for higher chlorine dosage to maintain appropriate levels of free chlorine residual if copper piping is used. PVC Pipes exhibited the least reactivity with free chlorine, indicative of the advantage of PVC as a premise Plumbing material for maintaining free chlorine residual. The reactivity of copper piping with free chlorine was significantly hindered by the accumulation of Pipe deposits. In contrast, the impact on chlorine decay by Pipe deposits was not significant in galvanized iron and PVC Pipes. Findings in this study are of great importance for the development of effective strategies for the control of free chlorine residual and prevention of microbiological contamination in premise Plumbing.