Shane Walker

Shane Walker
University of Texas at El Paso | UTEP · Department of Civil Engineering

Ph.D.

About

41
Publications
8,933
Reads
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1,014
Citations
Citations since 2017
29 Research Items
929 Citations
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2017201820192020202120222023050100150200250
2017201820192020202120222023050100150200250

Publications

Publications (41)
Article
Pervaporation is a vapor pressure-driven membrane desalination process that can desalinate water with greater total dissolved solids than conventional reverse osmosis. This review analyzes the performance (flux and permeance) of membrane materials used for pervaporation desalination. Poly(vinyl alcohol) (PVA), silica/silicate, graphene oxide (GO),...
Article
Water matrix composition impacts water treatment performance. However, matrix composition impacts have rarely been studied for electrochemical water treatment processes, and the correlation between the composition and the treatment efficiency is lacking. This work evaluated the electrochemical reduction of nitrate (ERN) using different complex wate...
Article
Full-text available
Per‐ and polyfluoroalkyl substances (PFAS), which are present in many waters, have detrimental impacts on human health and the environment. Reverse osmosis (RO) and nanofiltration (NF) have shown excellent PFAS separation performance in water treatment; however, these membrane systems do not destroy PFAS but produce concentrated residual streams th...
Article
Membrane separation has enjoyed tremendous advances in relevant material and engineering sciences, making it the fastest growing technology in water treatment. Although membranes as a broad-spectrum physical barrier have great advantages over conventional treatment processes in a myriad of applications, the need for higher selectivity and specifici...
Conference Paper
Full-text available
Mechanically stabilized earth (MSE) walls include galvanized steel reinforcements embedded within granular fills to add tensile strength and internal stability to the reinforced soil mass. The potential for corrosion of the steel reinforcements is managed by selecting fills to be non-corrosive, and this requires the implementation of proper techniq...
Article
Full-text available
Electrodialysis (ED) desalination performance of different conventional and laboratory-scale ion exchange membranes (IEMs) has been evaluated by many researchers, but most of these studies used their own sets of experimental parameters such as feed solution compositions and concentrations, superficial velocities of the process streams (diluate, con...
Article
Electrochemical advanced oxidation processes (EAOPs) have shown excellent capabilities to the abatement of recalcitrant organic pollutants. The Fenton-based electrochemical systems have shown great performance for in-situ generation of H2O2, allowing an efficient ●OH production for the mineralization of organic pollutants. These systems have been w...
Article
Full-text available
Reliable forecasts of water demand that account for factors that drive demand are imperative to understanding future urban water needs. The effects of meteorological dynamics and sociocultural settings are expressed weakly in many published municipal water demand models, limiting their utility for high-accuracy urban water demand modeling. To fill...
Article
Full-text available
Posttreatment of brine produced by reverse osmosis (RO) is a great challenge as it often requires high energy input and works at extreme operating conditions. In this study, brine from...
Article
Pervaporation desalination has several advantages over competing desalination technologies, most notably an ability to select for or against volatile organic compounds and the ability to process high salinity feeds at a low transmembrane pressure. Pervaporation has not been commercialized for desalination applications because of its energy intensit...
Article
Full-text available
Based upon an international workshop, this perspective evaluates how nano-scale pore structures and unique properties that emerge at nano- and sub-nano- size domains could improve the energy efficiency and selectivity of electroseparation or electrocatalytic processes for treating potable or waste waters. An Eisenhower matrix prioritizes the urgenc...
Article
Electro-driven technologies are viewed as a potential alternative to the current state-of-the-art technology, reverse osmosis, for the desalination of brackish waters. Capacitive deionization (CDI), based on the principle of electrosorption, has been intensively researched under the premise of being energy efficient. However, electrodialysis (ED),...
Article
Electrocatalytic-driven processes show promise for water purification, including abating persistent organic pollutants via advanced oxidation processes. Since the early 90s, thousands of research articles have systematically explored degradation of organic pollutants in batch systems and synthetic waters. Despite these research efforts, commercial...
Article
This study compares the scaling behavior of membrane distillation (MD) with nanophotonics-enabled solar membrane distillation (NESMD). Previous research has shown that NESMD, due to its localized surface heating driven by photothermal membrane coatings, is an energy-efficient system for off-grid desalination; however, concerns remained regarding th...
Article
Since the 1970s, The University of Texas at El Paso and El Paso Water have had a synergistic university–utility partnership, and in 2002, we began a sequence of investigations of enhanced recovery of water from silica‐saturated reverse osmosis concentrate: (a) two‐pass nanofiltration (NF) and reverse osmosis (RO) treatment, (b) lime softening for s...
Article
Polyethersulfone (PES) is commonly used polymer in ultrafiltration (UF) membranes which, due to its hydrophobic nature, frequently incorporates the copolymer, polyvinylpyrrolidone (PVP), to improve its hydrophilicity. Membranes are periodically disinfected using bleach which chemically degrades PVP, thus removing its hydrophilic advantage. The util...
Article
Technologies capable of selective removal of target contaminants from water are highly desirable to achieve "fit-for-purpose" treatment. In this study, we developed a simple yet highly effective method to achieve calcium-selective removal in an electrosorption process by coating the cathode with a calcium-selective nanocomposite (CSN) layer using a...
Article
Membrane capacitive deionization (MCDI) is a simple and low-cost method for brackish water desalination involving reversible electrosorption using high surface area, porous electrodes paired with ion-exchange membranes. Ion-exchange membranes improve charge efficiency and salt adsorption capacity by limiting the transport of co-ions and inhibiting...
Article
The resistivity of aggregates used as fill within mechanically stabilized earth (MSE) walls has been found to be a good indicator of its potential to corrode metal reinforcements. As such it is important to accurately measure the fill resistivity. Previous studies have found that resistivity is affected by the gradation of the material, as finer pa...
Article
The service life of mechanically stabilized earth walls depends on the corrosion rate of the metallic reinforcement used in their construction. The resistivity of the backfill aggregates needs to be measured accurately to estimate realistically the corrosion rate of the reinforcement. Resistivity testing is usually performed using the traditional s...
Article
Membrane Capacitive Deionization (MCDI) is a low-cost technology for desalination. Typically, MCDI electrodes are fabricated using a slurry of nanoparticles in an organic solvent along with polyvinylidene fluoride (PVDF) polymeric binder. Recent studies of the environmental impact of CDI have pointed to the use organic solvents in the fabrication o...
Article
Full-text available
Bisphenol A (BPA) and nonylphenols (NPs), with a high potential to cause endocrine disruption, have been identified at levels of nanograms per liter and even micrograms per liter in effluents from wastewater treatment plants. Constructed wetlands (CWs) are a cost-effective wastewater treatment alternative due to the low operational cost, reduced en...
Article
Full-text available
In Texas, Arizona, and New Mexico, colonias refer to unincorporated rural settlements along the U.S.–Mexico border. Colonias lack governance and public services normally provided by local government (Ward, 1999). Residents typically rely on well water or hauled water stored in above-ground containers. This study attempted to quantify and compare wa...
Article
It has been recognized that numerous synthetic compounds like Bisphenol A (BPA) and nonylphenols (NP) are present in effluents from wastewater treatment plants (WWTP) at levels of parts per billion (μg L-1) or even parts per trillion (ng L-1) with a high potential to cause endocrine disruption in the aquatic environment. Constructed wetlands (CW) a...
Article
Reverse electrodialysis (RED) can produce electric energy from waste heat using thermolytic solutions (e.g., NH4HCO3) where waste heat is used to regenerate the high concentration (HC) and low concentration (LC) solutions. The salinity difference between the two solutions in RED is converted into electric potential across an ion exchange membrane (...
Article
The objective of this research was to investigate the sensitivity of electrodialysis performance to variations in voltage application and membrane type when treating brackish water reverse osmosis (BWRO) concentrate waste, which typically exceeds multiple salt solubility limits. Synthetic BWRO concentrates from Arizona, Texas, and Florida of 7890-1...
Article
Full-text available
The objective of this research was to investigate the sensitivity of electrodialysis performance to variations in voltage application and membranes when treating brackish water reverse osmosis concentrate waste. Synthetic BWRO concentrates from Arizona and Texas of 7890-14,800 mg/L total dissolved solids were prepared with poly-phosphonate antiscal...
Article
In electrodialysis desalination, the boundary layer near ion-exchange membranes is the limiting region for the overall rate of ionic separation due to concentration polarization over tens of micrometers in that layer. Under high current conditions, this sharp concentration gradient, creating substantial ionic diffusion, can drive a preferential sep...
Article
The performance of electrodialysis is strongly dependent on the boundary layer thickness near an ion-exchange membrane. While a thinner boundary layer is known to enhance the ionic separation, the effects of statistical properties of the boundary layer thickness, such as the variation of the thickness and the correlation between the two boundary la...
Article
Full-text available
In ion-exchange membrane systems such as electrodialysis, the overlimiting current phenomenon still remains a difficult topic to study due to the complicated solution method for the Nernst–Planck–Poisson model. In this study, the Nernst–Planck–Poisson equations were prepared to simulate the steady-state binary ionic transport in the diffusion bound...
Article
Feasibility of an ED (electrodialysis) application to a drinking water softening process has been assessed using a mathematical model. A one-dimensional analytical model was built to describe the steady state ionic transport in an ED system by solving the Nernst-Planck equations with the electroneutrality assumption. The model simulates three ions...
Article
As a part of its Map Modernization Program, the Federal Emergency Management Agency (FEMA) specifies in the Guidelines and Specifications for Flood Hazard Mapping Partners how Flood Hazard Mapping Partners will submit geographic information system (GIS) data through the Digital Flood Insurance Rate Map (DFIRM) database (specified in Appendix L) and...

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