Acrylonitrile based engineering random copolymers were prepared via one step emulsion polymerization using ammonium persulfate (initiator), 1-dodecanthiol (chain transfer agent) and DOWFAX 8390 (surfactant) in the presence of water at approximately 65 0C. Three copolymer compositions were studied for novel polyacrylonitrile, (PAN)-polyhydroxyethyl acrylate (PHEA), PAN-polybutyl acrylate (PBA), novel PAN-polyt-butyl acrylate (PtBA), PAN-polyethyl acrylate (PEA) and PAN-polymethyl acrylate (PMA) with acrylate content varying from 8, 12 and 16 molar percent. Infrared spectroscopy, proton and carbon NMR were successfully utilized to confirm the chemical structure of copolymers. In order to determine the comonomer compositions in the copolymer structure, proton nuclear magnetic resonance, 1H NMR studies were carried out. Thermal (TGA, DSC) and mechanical properties of homo and copolymers were also investigated. Intrinsic viscosity (IV) measurements in dimethyl formamide (DMF) solution revealed that the molecular weight of the copolymers were quite enough to form ductile films. In this study, hydrogels and their copolymers of acrylonitrile (PAN-PHEA) were also studied. Some properties of the free standing copolymer films such as / swelling behaviors and densities were evaluated. It was also demonstrated that the nanocomposites of these copolymers could be utilized in filtration technology. Hence, novel PAN(88)-co-PMA(12) and polyaniline (PANI) nanocomposites were prepared at various PANI loadings to remove toxic chromium(VI) solution from water. Chemical structure, swelling and fracture morphology of the nanocomposites membranes were studied. It was observed that PANI had a great impact on the chromium removal. Permeate flux and rejection of chromium(VI) were demonstrated for various pHs and chromium(VI) concentrations. Finally, influences of comonomer composition on the thermal properties of the copolymers were investigated to input their structure property relation.

The aim of this study is to examine the technology of the relatively deteriorated historic tile, brick and mortar samples of Sivas G&ouml / k Medrese and Tokat G&ouml / k Medrese. Their main deterioration factors were analyzed mainly as salt weathering. It was examined in detail, and the possible desalination methods were discussed. For this purpose, the studies were carried out with a field survey and laboratory experiments on the two sites. Documentation of visual decay forms of Tokat G&ouml / k Medrese were done with AutoCAD. The density and porosities of tile body and mortar samples were determined by using RILEM standards. The pore size distributions of tile and mortar samples were examined by Mercury Intrusion Porosimetry. Modulus of elasticity of tile body and mortar samples was determined and compared with the other Seljuk building materials. Mineralogical compositions of the tile body and glaze, adhesive tile mortars of Sivas G&ouml / kmedrese and Tokat G&ouml / kmedrese were analyzed with X-Ray Powder Diffraction (XRD). Their microstructure and chemical compositions were determined by using Scanning Electron Microscope coupled with Energy Dispersive X-Ray Spectroscopy (SEM-EDX). The salts were determined for various methods such as spot tests and XRD analyses. The possible treatment methods of salt crystallization were discussed according to the properties of the examined samples. One of the most essential causes of decay factor was salt crystallization for the two buildings which causes detachment and loss of tiles. The deteriorations were distributed over the upper and lower sides of the wall which were close to the dampness zones from the roof and above ground. The experiments proved different kinds of salts such as thenardite, sylvite, halite, natrite, nitratine and niter coming from the ground and the restoration materials such as cement based mortars. The relative humidity of the environments was compared with that of salt characteristics. It was proved that the tiles were adversely affected from salt crystallization. The best desalination method was discussed. Advection method by using poultices was based on the transformation of ions through the flowing moisture. The most prominent characteristic of the poultices must have smaller pore size distribution than original salty materials. The pore size distributions of the tiles and gypsum mortars were determined to compare and chosen the best poultice from the literature. It was concluded that kaolin-sand-based poultices having known properties was the best one as considering the pore size distribution of the tiles and mortars. The study on material properties and desalination process was expected to help different monuments having salt problem.

The current reverse osmosis desalination membrane market is dominated by aromatic polyamide thin film composite (TFC) membranes. However, these polyamide membranes suffer from poor resistance to continual exposure to oxidizing agents such as chlorine in desalination applications. To overcome these problems, we have synthesized and characterized a new generation of materials, disulfonated poly(arylene ether sulfone) (BPS) random copolymer, for desalination membranes. A key technical feature of these new materials is their high tolerance to chlorine in feed water and their excellent reproducibility in synthesis. In this study, water and sodium chloride solubility, diffusivity and permeability in BPS copolymers were measured for both acid and salt form samples at sulfonation levels from 20 to 40 mol percent. The hydrophilicity of these materials, based on water uptake, increased significantly as sulfonation level increased. The water and salt diffusivity and permeability were correlated with water uptake, consistent with expectations from free volume theory. In addition, a tradeoff was observed between water/salt solubility, diffusivity, and permeability selectivity and water solubility, diffusivity and permeability, respectively. The influence of cation form and degree of sulfonation on free volume, as probed via positron annihilation lifetime spectroscopy (PALS), was determined in BPS random copolymers in both the dry and hydrated states. PALS-based free volume data for hydrated polymers were correlated with water and salt transport properties. The influence of processing history on transport properties of BPS films was also studied. Potassium form BPS films having a 32 mol% sulfonation level were acidified using solid state and solution routes. Additionally, several films were subjected to various thermal treatments in the solid state. The influence of acidification, thermal treatment, and counter-ion form on transport properties was investigated. Finally, the influence of synthesis methods of polyamide TFC membranes from m-phenylenediamine (MPD) and trimesoyl chloride (TMC) via interfacial polymerization on transport properties is reported. Then, a disulfonated diamine monomer (S-BAPS) was used instead of MPD to prepare TFC membranes. The resulting membranes exhibited reduced chlorine tolerance than those prepared from MPD. However, introduction of S-BAPS to the MPD/TMC polymerization system increased the fouling resistance of the resulting polyamide TFC membranes. / text

Many parts of the United States are facing water shortages. Planners have to ensure that there will be an adequate water supply to meet the needs of the growing population. Though many places encourage water conservation, and some even enforce water restrictions, this is not always enough to make up for the shortages. Thus, alternative water sources need to be considered in some cases. The states of Texas and Florida both face uncertainties with their future water supply. To meet the needs of their current and future populations, both states have recently been using desalination at a large scale to supplement their water supplies. This report examines the desalination facilities in El Paso, Texas and Tampa Bay, Florida to determine if desalination is a feasible water supply and to explore the consequences of pursuing the development of this water resource. / text

Water scarcity is among the most serious, long-term challenges in the world. To an ever increasing degree, sustainable water supply depends on the utilization of water of impaired initial quality. This is particularly true in developing nations and in water-stressed areas such as the American Southwest. Water of impaired quality could be water of high salinity such as brackish groundwater. Traditionally, reverse osmosis (RO) would be chosen to desalinate the brackish groundwater, since RO costs are competitive with those of thermal desalination, even for seawater applications. However, both conventional thermal distillation and RO are energy intensive, complex processes that discourage decentralized or rural implementation. In addition, both technologies require enhanced expertise for operation and maintenance, and are susceptible to scaling and fouling unless extensive feed pretreatment is employed. Membrane distillation (MD), driven by vapor pressure gradients, can potentially overcome many of these drawbacks. MD can operate using low-grade, sub-boiling temperature heat sources. When it is driven by solar energy it does not require highly concentrating collection devices, non-aqueous working fluids, or complex temperature control systems, nor does it require extensive operational expertise. Membrane Distillation (MD) applications, background and modeling efforts are discussed in the first part of this dissertation. Two main studies are presented in this document: Firstly, Sweeping Gas Membrane Distillation (SGMD) through a hollow fiber membrane was studied both experimentally and modeled mathematically to describe performance of SGMD and extend results to predict membrane module efficiency and secondly, SGMD through a flat sheet MD module to study the effect of membrane characteristics in combination with operational variables. A final study was conducted to examine the effect of mesh spacer insertion in flat sheet membrane module on the permeate water production.

Concentrate (when discharged to the ocean) may have chronic/acute impacts on marine ecosystems, particularly in the mixing zone around outfalls. The environmental impact of the desalination plant discharges is very site- and volumetric specific, and depends to a great extent on the salinity tolerance of the specific marine microbial communities as well as higher order organisms inhabiting the water column in and around this extreme discharge environment. Scientific studies that aim to grant insight into possible impacts of concentrate discharge are very important, in order to understand how this may affect different marine species when exposed to elevated salinity levels or residual chemicals from the treatment process in the discharge site. The objective of this PhD research was to investigate the potential environmental effects of the concentrate discharge in the near-field area around the submerged discharge of the King Abdullah University of Science and Technology (KAUST) seawater reverse osmosis (SWRO) plant by a combination of biological and hydrological studies. Possible changes in microbial abundance were assessed by using flow cytometric (FCM) analysis on a single-cell level in 107 samples, taken from the discharge area, the feed-water intake area and two control sites. Results indicate that changes in microbial abundance in the near-field area of the KAUST SWRO outfall are minor and appear to bethe result of a dilution effect rather than a direct impact of the concentrate discharge. In order to also investigate potential impacts on higher order organisms, a longterm in-situ salinity tolerance test at the discharge site was conducted on the coral Fungia granulosa and its photophysiology. The corals were exposed to elevated levels of salinity as a direct result of concentrate discharge. Their photosynthetic response after exposure to extreme salinity conditions around the full-scale operating SWRO desalination discharge was measured. A pulse amplitude modulated (PAM) fluorometer was used to assess photochemical energy conversion in photosystem II (PSII) measured under constant concentrate discharge conditions. Based on a literature review, we anticipated distinct impairment of photosynthetic characteristics as a response to elevated salinity levels. We also expected particularly quick indications of bleaching for the specimens exposed to the highest salinity levels. The hypothesis was strongly rejected as symbiotic dinoflagellates of Fungia granulosa demonstrated high tolerance to hyper saline stress as measured by effective quantum yield of PSII (ΔF/Fm’) during this study. A series of propulsion driven autonomous underwater vehicle (AUV) missions with velocity and salinity measurements were used for possible plume detection and evaluation of the discharge. The Cornell Mixing Zone Expert System (CORMIX) was additionally utilized in order to assess discharge performance under different ambient velocity magnitudes. Results show that AUV missions could provide significant insight with regards to plume identification and effluent discharge environmental impact studies. Combined with robust in-situ field measurements, models and expert systems were used to evaluate possible impacts on the marine environment in comparison with regulatory mixing zones and dilution criteria. Based on the findings and existing environmental governance (national and international), a revised regulatory framework for mixing zones within the Kingdom of Saudi Arabia is recommended.

From the Proceedings of the 1974 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 19-20, 1974, Flagstaff, Arizona / The process of salt replacement desalination proposed is believed to be able to produce vast quantities of fresh water be desalination. This method, which is a novel approach to minimizing the costs of saline water conversion, consists of the substitution of solutes in a solution to be desalted by a replacer chemical, and the low energy removal of that replacer chemical. The ultrafiltration of larger molecular sized replacer chemicals with high flux membranes increases the produce yield rate and reduces the corresponding energy requirement, with respect to reverse osmosis. In addition, the initial captial investment is less since no pressure constraining devices are required. The alteration of the osmotic pressure of the replacer solution within the process can also take advantage of energy savings through the utilization of an easily reversible reaction which synthesizes and breaks down a constituent that has a significant osmotic pressure difference between phases. Finally, the unusual process of fixed gel syneresis shows potential as a low energy salt replacement type process, but still requires extensive investigation.

The provision of freshwater, particularly in urbanizing arid regions facing increased variability in precipitation patterns due to climate change, is one of the greatest challenges. Desalination--the conversion of seawater or brackish water to potable water--offers a potentially "limitless" supply of this vital resource. The preference for desalination, as an innovative, supply-side water augmentation option is gaining traction worldwide, including in northwestern Mexico. In arid regions, where water is a limiting factor to increased production and growth and nearly every drop of water is contested, a new technology that augments water supplies is likely to engender vast social, economic, institutional, and environmental transformations. Through an in-depth study of water management in the context of global climate change in northwestern Mexico, this dissertation examines the factors that lead to the adoption of desalination technology and assesses how the technology affects the communities where it is implemented. In seeking to understand the (potential) transformations and complex imbrications of this technology within the socioecological system in which it operates, four themes have emerged, including: 1) The best path towards improved water management is through investments in both infrastructure and institutions (i.e., governance); 2) Despite the real and urgent need to address the negative impacts of climate change on water resources, desalination should be considered as a "last resort"; 3) While desalination can increase water security at certain scales, it also introduces new vulnerabilities; and 4) While discursively, Mexico's water policy embraces principles of contemporary environmental governance (i.e., decentralization, public participation, and sustainability), these principles have yet to be fully implemented in practice. Policy recommendations include integrating land use and water planning, improving monitoring and regulation of groundwater extraction, increasing capacity building within water and planning agencies, and pre-conditioning desalination (or other supply-side water infrastructure projects) upon the successful implementation of a range of water conservation and system efficiency measures. Without such measures, increased water availability is likely to encourage additional growth, rather than resource conservation. Specific findings and contributions of this dissertation to the field of human-environment geography are discussed at the end of chapter two and in the appended articles.

Water scarcity is one of the biggest issues we have to face as population and water consumption levels increase despite a fixed supply of renewable fresh water. Meeting the challenges that water scarcity poses to food production, ecosystem health, and political and social stability will require new approaches to using and managing water. Desalination already plays an essential role in water management. It constitutes a secure source of safe drinking water supply once demand management measures are fully implemented. Overcoming problems related to brine minimization and disposal is key to sustainable, efficient inland water desalination. The main focus of this was the investigation of technical limits and improvements for application in inland desalination. The first part of the dissertation covers the study of Membrane Distillation (MD) for desalination of water. The second part provides a broad perspective of Reverse Osmosis (RO), pretreatments -comparison of slow sand filtration and microfiltration-, post-mortem study of membranes to determining fouling and scaling causes, and RO brine minimization via Vibratory Shear Enhance Processing (VSEP®) for use in RO brine minimization. The study of Vacuum Membrane Distillation in a hollow fiber membrane was studied. Experimental work is supported by an original mathematical model to expose the physics of VMD and support predictions that extend VMD results beyond these generated in the laboratory. The advantages and disadvantages of each pretreatment, including their effects the effect on the performance of RO, a post-mortem membrane study and an economic analysis. The post-mortem study of membranes used during Yuma Desalting Plant operation. This work was used to identify the best pretreatment and more suitable membrane to treat saline water in the lower Colorado River. The work performed during the brine minimization study using VSEP®. This study included experimental data and an extensive economic analysis comparing Ion Exchange (IX) as pretreatment and VSEP® as post-treatment for RO.

This thesis focuses on the development of two new applications using ion concentration polarization (ICP): an out-of-plane microfluidic approach for water desalination and a method for concentration and transportation of charged analytes in paper-based biomedical diagnostic device. In the first work, we present an out-of-plane desalination approach using ICP. A depletion boundary separates salt ions and purified water into distinct vertically stacked layers. The out-of-plane design enables multiplexing in three dimensions, providing the functional density required for practical applications. The second work demonstrates an active control mechanism of target analytes in paper using ICP. Both external devices (with all functional units on one side of paper) and integrated paper microfluidic devices (by embedding all functional units in paper) were developed to concentrate and transport charged analyte molecules in the paper. We also demonstrate a new fabrication method of nanofluidic and hydrophobic barriers (nanoporous membrane patterning) in paper microfluidic device.