Use Of Seawater Research Articles

Mechanistic Insights into Electrodeposition in Seawater at Variable Electrochemical Potentials

AbstractThe classical approach to manufacturing cement and concrete involves considerable and energy‐intensive exploitation of minerals from the environment, calling for alternative and sustainable methods to obtain such resources. Electrodeposition resulting from local pH changes near an oxygen or water reduction electrode can be used to grow valuable minerals in seawater for use in the cement and concrete industries, with the potential to use clean electricity without relying on the mining of resources. Limited knowledge is available about the electrochemical reaction networks that yield mineral precipitates via electrodeposition in seawater, hindering a complete assessment of the promise of such an approach to serving the construction industry. This work presents an investigation of the electrodeposition in seawater as a function of the applied potential. The work identifies multiple electrochemical potential regimes that yield distinct polymorphs, quantities, and production rates of calcium and magnesium‐based minerals due to the varying rates of oxygen reduction and water‐splitting reactions. The quality of the produced minerals is comparable to that of traditionally mined aggregates in terms of morphology and composition, supporting that seawater represents a vast source of raw materials for use in the construction industry upon an enhancement in the efficiency of hydroxide‐producing reactions and the reactor design.

Self-Compacting High-Strength Textile-Reinforced Concrete Using Sea Sand and Sea Water.

In this study, a self-compacting high-strength concrete based on ordinary and sulfate-resistant cements was developed for use in textile-reinforced structural elements. The control concrete was made from quartz sand and tap water, and the sea concrete was made from sea water and sea sand for the purpose of applying local building materials to construction sites in the coastal area. The properties of a self-compacting concrete mixture, as well as concrete and textile-reinforced concrete based on it, were determined. It was found that at the age of 28 days, the compressive strength of the sea concrete was 72 MPa, and the flexural strength was 9.2 MPa. The compressive strength of the control concrete was 69.4 MPa at the age of 28 days, and the flexural strength was 11.1 MPa. The drying shrinkage of the sea concrete at 28 days exceeded the drying shrinkage of the control concrete by 18%. The uniaxial tensile test showed the same behavior of the control and marine textile-reinforced concrete; after the formation of five cracks, only the carbon textile reinforcement came into operation. Accordingly, the use of sea water and sea sand in combination with a cement with reduced CO2 emissions and textile reinforcement for load-bearing concrete structures is a promising, sustainable approach.

Effect of seawater on solidification/stabilisation treatment of marine soft soil slurry by lime-activated ISSA and GGBS

It is proposed to use dredged marine sediments as fill material in marine reclamation engineering by stabilisation/solidification (S/S) technology with sustainable binding materials, which can help the soft soil gain strength to solve the engineering geological problem of its insufficient bearing capacity. In this work, lime and two types of industrial wastes, i.e., incinerated sewage sludge ash (ISSA) and ground granulated blast-furnace slag (GGBS), were selected as the binding materials. Hong Kong marine deposits (HKMD) slurry with a high initial water content of 110% was mixed with 30% binders (30% lime and 70% (ISSA+GGBS) with ISSA: GGBS = 3). The seawater (SW) with salinity of 3.6% was employed as mixing solution in S/S treatment of HKMD. To detect the effect of each main composition in SW on the performance of S/S HKMD, the pure solutions of NaCl, MgCl2 and Na2SO4 were adopted in this study.The results show that the use of SW in the lime-activated ISSA and GGBS treated dredged HKMD slurry is effective in improving its strength. The X-ray diffraction, thermo-gravimetric analysis and scanning electron microscopy observations present the formation of calcium/magnesium silicate hydrate (C/M-S-H), Friedel's salt and ettringite, which fill into the pores and interlock the particles in the mixture increasing the strength of the treated HKMD. The chemical compositions of SW have significant and different impacts on the performance of treated HKMD samples. Na+ can help the samples gain higher strength and result in the cracking development in the S/S samples. Mg2+ will lead to the formation of M-S-H, which reduces the porosity of treated HKMD samples. However, the contribution of M-S-H to the soil strength is less than that of C-S-H. Cl− in the mixture would slow down the reaction speed and show slight impacts on the modulus. SO42− accelerates the reactions in the treated samples and has a more significant effect on nano-size porosity of bulk sample. Consequently, the seawater has positive effect on the S/S performance of HKMD slurry, suggesting potential application in the practical projects.

Review on Technology-Based on Reverse Osmosis

Reverse osmosis (RO) is a membrane filtering system that uses a semipermeable membrane to remove contaminants from water before sending the purified water on to be used in a number of settings, such as households and factories. The goal of this study is to investigate the process of reverse osmosis as well as the current status of the membrane materials that are used in the process. These membrane materials are the driving elements in the process. This review also includes a discussion on the cleaning of membranes, the utilization of RO systems for a number of applications, and new advancements in the field of reverse osmosis. In the process of cleaning water, reverse osmosis, also known as RO, is a potent technique that makes use of a semi-permeable membrane to remove hazardous bacteria as well as dissolved particles. This technique is utilized on a regular basis for the purpose of desalinating seawater for use in drinking, agricultural, and industrial applications.

Hydration of Portland cement with seawater toward concrete sustainability: Phase evolution and thermodynamic modelling

To mitigate the shortage of freshwater resource in the island and coastal regions, using seawater (SW) for concrete mix can provide significant economic and environmental benefits. To achieve a safe and reliable application, in-depth investigation is needed on hydration of Portland cement in SW. The composition of solid and liquid phases in hydrated Portland cement was quantitively determined and analysed in this study. The use of SW not only significantly increases the hydration rate of clinker but also affects the evolution of phase assemblage. Both the thermodynamic calculations and experimental determinations indicates the formation of Friedel's salt (FS) instead of sulfo-AFm in hydrated cement by SW, implying sulfate ions cannot compete with chloride ions to combine with AFm phases. The characteristic reaction in SW leads to higher sulfate concentration, thus indirectly hindering ettringite (AFt) conversion at the late stage. Through the experimental quantification of thermogravimetric analysis and X-ray diffraction analysis, the kinetic model of clinker dissolution was modified to be more suitable for the hydration of Portland cement in SW. The calculation from coupled models exhibits a novel method to evaluate the evolution of phases in cement hydration. Through model calculations, 3.70% higher solid volume and 12.2% lower liquid volume were obtained in the cement-SW paste at the end of the hydration, which may cause the mechanical properties to be more sensitive under environmental humidity and the temperature.

Behaviour of rubberised concrete with waste clay brick powder under varying curing conditions

Recently, there has been a worldwide scarcity of pure water for curing concrete and this has called for alternative curing conditions including utilisation of sea water. An experimental study was conducted to examine the mechanical behaviour of rubberised concrete with waste clay brick powder (WCBP) under different conditions of curing including water and sea water. The samples of rubberised concrete incorporated with WCBP were cured in water and sea water for 90 days curing period. The findings showed that the conventional and modified concrete mixtures which were cured in sea water illustrated reduced compressive and split tensile strengths compared with corresponding mixes cured in water. Among specimens cured in each curing condition, concrete mixes with 5% WCBP showed increased compressive and split tensile strengths compared with the control concrete mixes. The lowest compressive and split tensile strength findings were noticed with rubberised concrete incorporated with WCBP. The comparisons of densities of specimens cured in water and sea water showed no significant distinctions between the curing conditions. Compressive strength seemed to be less sensitive to conditions of curing compared with split tensile strength. From the findings, minor reductions in compressive strengths for samples cured in sea water compared with those cured in water were suggested to be reflections of possibility of utilising sea water as a curing agent in areas where pure water is very scarce. The findings in this study seem to suggest that the use of sea water in concrete curing should not be feared and could be welcome, particularly in offshore constructions and isolated islands.

Current ecological state of soils in the Caspian lowland of Azerbaijan and conditions of their formation

The article presents an analysis of the current ecological state of the lands of the Caspian coastal territories within the borders of the Republic of Azerbaijan and outlines the influence of various factors on the ecological state of these soils. In the course of scientific research carried out according to numerous criteria, an assessment was made of the current reclamation situation in the coastal areas of the Caspian Sea. It has been established that the ecological situation of the region is very tense and the process of desertification occurs due to a lack of water in the region, located in an arid zone. To improve the reclamation state of the territory, it is recommended to use additional water sources and non-traditional irrigation - Caspian sea water with a mineralization index of 12-14 g/l as irrigation water. The occurrence of groundwater in this region at a depth of 5-10 m from the surface of the earth and its low degree of mineralization allows the use of sea water to irrigate the soils of these areas during the growing season, which creates conditions for the transport of salts accumulated in the upper layer of soil to the lower layers. As a result of a complete study and analysis of the physical, mechanical, chemical and water-physical properties of the soil, it was finally concluded that when cultivating Caspian lands for agricultural crops, non-traditional irrigation waters, especially water from the Caspian Sea, can be used for irrigation. This is possible due to the soil characteristics of the region. The use of sea water for irrigation purposes will have a positive impact on the revitalization of coastal lands that have not been cultivated for years due to lack of water, and will contribute to the abundance of harvests in the republic.

Возможности применения промышленной воды предприятий нефтегазового комплекса для получения противопожарных пен

Introduction. One of the distinctive features of fires at oil and gas facilities is the need for constant replenishment of the water supply used by fire departments in the shortest possible time. There is a need for the use of industrial waters in the organization of extinguishing fires of oil and petroleum products. In this paper discusses the features of the usage of industrial waters to obtain premixes of foaming agents used for foam fire extinguishing. For this purpose, an assessment of the technical indicators of the quality of working solutions of foaming agents was carried out using models of drinking, circulating and seawater. Goals and objectives. Conducting research on the foaming ability of standard foaming agents with water, in its composition as close as possible to the requirements of regulatory documents to recycled industrial water. Methods. The following laboratory methods were used in the work: volumetric analysis, complexometric titration, tensiometry, standard methods of testing foaming agents to assess their quality. Results and discussion. The total salinity in waters of various types increases in the range from drinking to sea water. Recycled water at the maximum values of salt additives occupies an average intermediate value, including in terms of water hardness, which gave a difference in foaming characteristics. The difference between the hardness of drinking and model circulating water is significant, which affects the foaming due to the flow of ionic processes in such systems and probably leads to a decrease in expansion factor of the resulting air-mechanical foam. The possibility of using industrial waters to produce firefighting foams has been experimentally confirmed. A model of recycled industrial water has been developed, which made it possible to evaluate the extinguishing efficiency of foam obtained on its basis in laboratory conditions. Conclusion. A comprehensive analysis of the obtained data shows that foaming agents, application field of which does not imply the use of sea water, can be used to prepare premixes in ordinary drinking water, as well as in recycled water used in the technological cycles of industrial enterprises, which in some cases simplifies the practical issues of obtaining fire-fighting foams for extinguishing fires. Keywords: foaming agents; recycled industrial water; water hardness; air-mechanical foam.

Efficient Use of Water in Tailings Management: New Technologies and Environmental Strategies for the Future of Mining

Nowadays, many major copper mining projects in desert areas with extremely dry climates, as in northern Chile and the southern coast of Peru, process sulfide ores at high production rates; in some cases over 100,000 metric tonnes per day (mtpd), generating large amounts of tailings, that are commonly managed and transported to tailings storage facilities (TSF) hydraulically using fresh water. Considering the extremely dry climate, water scarcity, community demands, and environmental constraints in these desert areas, the efficient use of water in mining is being strongly enforced. For this reason, water supply is recognized as one of the limiting factors for the development of new mining projects and for the expansion of the existing ones in these areas. New water supply alternatives, such as sea water desalinization, direct use of sea water, or water recovery from tailings, represent the strategy developed by the mining industry to deal with this growing scarcity. The focus of this paper is the possibility of applying different water supply technologies or a combination of these, implementing improved water management strategies that consider: environmental issues, technical issues, stringent regulatory frameworks, community requests and cost-effective strategies, that result in a reduction of freshwater make-up water requirements for mining (m3 per metric tonnes of treated ore).

A comparison between alkali‐activated slag/fly ash binders prepared with natural seawater and deionized water

AbstractIn this research, the effects of natural seawater (SW) on the properties of alkali‐activated slag/fly ash (AASF) are studied. AASF prepared with deionized water is set as the reference mixture. The results showed that the use of natural SW resulted in a prolonged setting time and lower heat release, but no obvious impact on the flowability of AASF specimens. The long‐term compressive strength became higher when SW was used, whereas the corresponding flexural strength and fractural toughness turned lower. The use of SW induced the formation of new products that were not identified in the reference mixture, such as Cl–hydrocalumite and gypsum. In addition, it is evidenced that the dissolution of fly ash (FA) particles was significantly delayed with the incorporation of SW. All these results were related to the various ions introduced by the natural SW and their interactions with the alkaline activator as well as the precipitation of salts on slag and FA surfaces or in the matrix.

Use of Sea Water as Fertilizer

Use of Sea Water as Fertilizer

Use of Sea Water as Fertilizer

Use of Sea Water as Fertilizer

ОБЗОР МЕТОДОВ И ТЕХНОЛОГИЙ ОПРЕСНЕНИЯ ВОДЫ ДЛЯ ЦЕЛЕЙ ПИТЬЕВОГО ВОДОСНАБЖЕНИЯ

Purpose: review of existing technologies and methods of seawater desalination for drinking water supply. Discussion. Based on modern research methods using statistical data and a review of domestic and foreign literature, a review of methods and technologies for desalination and desaltation of highly mineralized natural waters was carried out. The use of sea water for domestic purposes is impossible due to the high content of minerals, however, after desalination, such water can be used for drinking. The choice of technologies and methods of desalination is primarily determined by the quality of source water, as well as the requirements for the quality of treated water, plant productivity and technical and economic calculations. For the drinking water supply purposes, the most efficient and cost-effective method is desalination using reverse osmosis technology, used for both sea and groundwater with high salinity. Reverse osmosis technology has significant advantages over thermal desalination, especially when applied to small-scale plants of small domestic water supply systems. The use of reverse osmosis plants will significantly increase productivity of drinking water output per watt of electricity consumed. Conclusions. The introduction of modern technologies and careful attention to water consumption play a significant role in maintaining water balance in different countries. The most cost-effective and efficient method is seawater desalination using reverse osmosis plants. Despite the fact that water desalination and desaltion plants are very expensive, the conservation of natural waters is a priority nowadays.

Early-age and microstructural properties of glass powder blended cement paste: Improvement by seawater

The incorporation of conventional supplementary cementitious materials (e.g. fly ash) in concrete generally induces a longer setting time and inferior early-age strength. This study aims to evaluate the effectiveness of using seawater (SW) as mixing water in improving the early-age properties of cement pastes/mortars prepared with waste glass powder (WGP) which has a low reactivity. By means of measurements of rheological behaviors, macro/micro mechanical properties, hydration kinetics of the WGP blended cement with SW, and other microstructural analytical techniques, the early-age performances were investigated. The results showed that the incorporation of WGP increased yield stress and plastic viscosity of the cement paste due to its fine particle size, negative surface charge and hydrolysis effect. The use of SW further changed the rheological properties by accelerating the hydration of cement. The dissolved ions from the WGP and the presence of SW in the cement paste were beneficial to shortening the prolonged setting time induced by the replacement of cement by the WGP. The combined use of SW was effective in overcoming the inferior early-age strength caused by the dilution effect of WGP inclusion at the very early age. The enhanced precipitation of hydration products, increased degree of hydration, refined pore structure were responsible for the increase of the early-age strength of the WGP blended cement prepared with SW.

Eco-Friendly Innovation for Electrical Conductivity Reduction of Persian Gulf Sea water Using Highly Efficient Recyclable Sorbent

The use of sea water containing of Reverse Osmosis effluent is very serious for the daily living of the coastal residents especially for farmers. In this study, one-year field test was carried for electrical conductivity reduction of Persian Gulf sea water in Iran, during 2017 and 2018. The test was conducted in two filters each with diameter 2.5 cm (or 0.025 m) and 18.5 cm (or 0.185 m). In the filters, crumb mineral mussel was used as one of main components from filter materials. The minor components of filter materials were comprised of coarse-grained gravel, fine-grained activated carbon, and fine-grained sand. The well water as low-saline water for background of sea water treatment and sea water as super-saline water were treated. The test was performed as pilot, batch, and column design with three replicates. The volume of daily treated sea water and efficiency of reduction electrical conductivity and salinity were determined. Volume of treated sea water by each of the filters was at least 10 times diameter each of those. Maximum reduction efficiency of electrical conductivity and salinity in filter with 2.5 cm (or 0.025 m) diameter was 97.09% (from 85.2 to 2.48 mS/cm or from 8.52 to 0.248 S/m) and it was 98.2% (from 61 to 1.1), respectively. Maximum reduction efficiency of the parameters in filter with 18.5 cm (or 0.185 m) diameter was 97.5% (from 84.8 to 2.12 mS/cm or from 8.48 to 0.212 S/m) and it was 97.69% (from 60.7 to 1.4), respectively. Electrical conductivity in outlet water from filters was less than 3 mS/cm (or 0.3 S/m), below the permissible limit recommended by World Health Organization and also Iranian Department of Environment for agriculture and irrigation usage. Based on these results a non-continuous method seems promising in the biological growing phase in filters.

Sea Water-Based Medicines: Manufacturing Technology and Standardisation

Sea water and sea salt obtained from it are widely used as substances in the production of medicinal products. Complex chemical composition of sea water which contains various salts, calls for the development of a common quality standard for sea water-based medicines. The aim of the study was to analyse and summarise available data on the sources of sea water-based medicines, and on the current test methods, as well as to develop a unified approach to quality control. The paper summarises information on the use of sea water for medical purposes. It presents comparative data on the chemical composition of sea water obtained from different sources, manufacturing technologies of sea water-based medicines, and composition of medicines produced from sea water or sea salt. The paper summarises data on the use of sea water for the production of various dosage forms: drops, sprays, aerosols. The study revealed qualitative and quantitative differences in the content of major cations and anions in drug products. The authors analysed the use of various chemical and physico-chemical test methods for qualitative and quantitative characterisation of medicines. It was concluded that there is a need to harmonise quality control methods for sea water-based medicines.

Evaluation of the Use of Sea Water as a Diluent for an Accelerated Hydrogen Peroxide Disinfectant for Inactivation of Avian Influenza Virus: A Surrogate for Infectious Salmon Anemia Virus.

Introduction: Use of sea water as a diluent for disinfectants has been of practical interest for control of aquaculture disease outbreaks in sea where fresh water is limited. This study evaluated the use of natural sea water (NSW), artificial sea water (ASW), or standard hard water (SHW) as a diluent for preparation of accelerated hydrogen peroxide (AHP) solutions against an avian influenza virus, a surrogate for the infectious salmon anemia virus. Methods: AHP solutions containing 0.18%, 0.35%, or 0.44% (w/w) of hydrogen peroxide (H2O2), corresponding to 1/40, 1/20, and 1/16 dilutions of the disinfectant concentrate, were evaluated at -20°C, 4°C, and 21°C. Results: When NSW was used as the diluent, a 0.35% H2O2 concentration was required to inactivate ∼6 log10 virus at 21°C in a 5-min contact time. When temperature dropped to 4°C, 0.44% H2O2 in NSW was required to obtain a similar inactivation within a 5-min contact time. At -20°C, supplemented with antifreeze agents, the 0.44% H2O2 in NSW solutions produced complete inactivation of 5.4 log10 virus within a 10-min contact time. In comparison, lower H2O2 concentrations and/or shorter contact times were needed to inactivate equal amounts of the virus at the same temperature when using SHW or ASW as a diluent to prepare disinfection solutions. Conclusion: The results suggested that NSW could be used as a diluent in disinfection solutions for virus inactivation as long as disinfectant concentrations and/or contact times are properly increased.

Dyeing of cotton with reactive dyes using pre-treated sea water

The present study explores the use of sea water as dyeing medium for cotton textiles with reactive dyes. Sea water has been pre-treated with calcium oxide/sodium carbonate to remove calcium and magnesium ions. The findings show that the addition of 20 g/L of sodium chloride is required to increase the exhaustion of dye in pre-treated sea water instead of 60 g/L of sodium chloride as required in conventional dyeing method. SEM , KESF and EDAX analyses show no significant difference on the surface of pre-treated sea water dyed and conventional dyed fabrics. It is also found that there is no significant difference in the wash and light fastness properties between pre-treated sea water dyed fabrics and conventional dyed fabrics. The developed process is in the direction of addressing sustainability issues of textile processing industries.

Pore and strength characteristics of alkali-activated slag paste with seawater

This study investigates the pore and strength characteristics of alkali-activated slag paste, using seawater (SW) and tap water (TW) as the mixing water. During the investigation, the water/binder ratio was 0·45 and the activator used was sodium hydroxide (NaOH). Activator concentrations of 2, 4 and 6% of the binder weight were used. The compressive strength was measured and X-ray diffraction, mercury-intrusion porosimetry (MIP) and scanning electron microscopy analyses were conducted to determine the cause of the change in strength and pore structure. The results indicate that the compressive strength for early and later ages improved with the use of SW instead of TW. When SW was used, calcium–silicate–hydrate gel and Friedel's salt were identified as the hydration reactants. Based on the MIP measurements, when the sodium hydroxide concentration was increased, the pore size and number of pores decreased to form a denser matrix. In particular, samples containing SW had an increased number of gel pores (<0·01 μm).

A comparative analysis of shielding of thermal radiation of fires using mist curtains containing droplets of pure water or sea water

The paper is focused on comparative computational modelling of the attenuation of fire radiation by water mists of pure water or sea water. The use of sea water in fire protection could be a more convenient and practical choice in coastal areas, on offshore installations or transported ships. The spectral absorption and scattering properties of both water droplets and salt particles formed by evaporation of sea water droplets are considered. A combined heat transfer problem is based on a combination of the spectral radiative transfer in a mist curtain, the kinetics of water evaporation, and convective heat transfer along the curtain. The developed computational model is used to analyze the radiative heating and evaporation of droplets of pure water and more complex multi-phase processes in droplets of sea water at all stages of the process. The numerical results for the case problem indicate sufficiently good shielding quality of a sea-water mist curtain. The suggested approach is expected to be useful for important engineering applications in fire protection.