Water Reverse Osmosis Desalination Research Articles

Optimization of a Biomass-Based Power and Fresh Water-Generation System by Machine Learning Using Thermoeconomic Assessment

Biomass is a viable and accessible source of energy that can help address the problem of energy shortages in rural and remote areas. Another important issue for societies today is the lack of clean water, especially in places with high populations and low rainfall. To address both of these concerns, a sustainable biomass-fueled power cycle integrated with a double-stage reverse osmosis water-desalination unit has been designed. The double-stage reverse osmosis system is provided by the 20% of generated power from the bottoming cycles and this allocation can be altered based on the needs for freshwater or power. This system is assessed from energy, exergy, thermoeconomic, and environmental perspectives, and two distinct multi-objective optimization scenarios are applied featuring various objective functions. The considered parameters for this assessment are gas turbine inlet temperature, compressor’s pressure ratio, and cold end temperature differences in heat exchangers 2 and 3. In the first optimization scenario, considering the pollution index, the total unit cost of exergy products, and exergy efficiency as objective functions, the optimal values are, respectively, identified as 0.7644 kg/kWh, 32.7 USD/GJ, and 44%. Conversely, in the second optimization scenario, featuring the emission index, total unit cost of exergy products, and output net power as objective functions, the optimal values are 0.7684 kg/kWh, 27.82 USD/GJ, and 2615.9 kW.

Environmental health risk of brine disposal for reverse osmosis water desalination plants: A case study in Bandar Abbas city, Iran

Reverse osmosis desalination brine (RODB) is a concentrated by-product containing higher salinity and turbidity and chemicals added to the raw water. As the RODB discharge has caused many environmental concerns, this case-control study investigated the (RODB) impact on the coastal environment. Five RODB Receiving beaches and one control point were selected, 84 samples of RODB, seawater, and coastal sediments were taken then chemical, physical, and biological parameters were measured. As well as environmental risk was assessed. The seawater salinity and turbidity on the RODB-receiving beaches were higher than the control point, and the population and diversity of plankton were lower. The content of some heavy metals was higher in the sediments affected by RODB. Low to moderate degrees of heavy metal-related environmental threat was calculated. The discharge of RODB leads to changes in the coastal ecosystem quality and can be an environmental hazard, therefore, it requires serious monitoring and control programs.

Fast Water Desalination with a Graphene-MoS2 Nanoporous Heterostructure.

Energy-efficient water desalination is the key to tackle the challenges with drought and water scarcity that affect 1.2 billion people. The material and type of membrane in reverse osmosis water desalination are the key factors in their efficiency. In this work, we explored the potential of a graphene-MoS2 heterostructure membrane for water desalination, focusing on bilayer membranes and their advantages over monolayer counterparts. Through extensive molecular dynamics simulation and statistical analysis, the bilayer MoS2-graphene was investigated and compared to the monolayer of graphene and MoS2. By optimizing the heterostructure membrane, improved water flux was achieved while maintaining a high ion rejection rate. Furthermore, the study delves into the physical mechanisms underlying the superior performance of heterostructure nanopores, comparing them with circular bilayer and monolayer pores. Factors investigated include water structure, hydration shell near the membrane surface, water density, energy barrier using the potential of mean force, and porosity within the nanopore. Our findings contribute to the understanding of heterostructure membranes and their potential in enhancing the water desalination efficiency, providing valuable insights for future membrane design and optimization.

Synthesis of high-performance biocompatible polymeric membranes incorporated with zirconium-based MOF for an enhanced brackish water RO desalination

A nanosized zirconium 1,4- dicarboxybenzene metal-organic framework (UiO-66-MOF) was synthesized and impregnated into cellulose acetate (CA) polymeric matrix to enhance the membrane characteristics for brackish water desalination. Phase inversion was used for the fabrication of CA/UiO-66 hybrid membranes (CAU-X), where X is the concentration of immobilized UiO-66 nanoparticles (UiO-66-NPs) into CA polymeric matrix. Morphological structure and functional groups were investigated through different characterization techniques to prove the successful synthesis of the prepared UiO-66-NPs, the blank CA membrane, and hybrid CAU-X membranes. For more CAU-X characteristics, porosity, contact angle, and tensile strength were measured. The obtained data demonstrated that the impregnation of zirconium-based-NPs had a positive influence on the blank CA membrane properties. Additionally, the performance of the fabricated membranes was investigated in reverse osmosis (RO) bench-scale unit. The performance results for the pristine CAU-0 membrane showed a high salt rejection (SR) of 99.8% and a permeate water flux (PWF) of 1.14 L/m2.h. In comparison to pristine CA membrane, CAU-X hybrid membranes have a slightly lower SR and a higher PWF. It was found that the hybrid CAU-0.02 membrane had almost a doubled PWF of 2.8 L/m2.h with only 2% sacrificed SR of 97.6% compared with CAU-0 membrane. Moreover, a much better PWF of 3.4 L/m2h and a sufficient SR of approximetly 92% were obtained by CAU-0.05 membrane. Thus, CAU-0.05 was selected to further test its performance under different operating parameters. Results revealed that the optimum parameters were recorded for a sodium chloride feed stock of 5000 ppm operating at 25 °C temperature and pressure up to 15 bar.Graphical

Desalination performance investigation of TpPa-1 COF and MIL-47(V) MOF bilayer membranes using molecular dynamics simulation

The efficiency of reverse osmosis (RO) desalination heavily depends on the advancement of innovative membrane materials. In this study, we utilized molecular dynamics simulations to assess the desalination performance of pure and hybrid bilayers made from two-dimensional (2D) TpPa-1 COF and MIL-47 (V) MOF materials. Our findings show that a pure TpPa-1 COF bilayer exhibits a water permeability (348 L/cm2/day/MPa) that is over four orders of magnitude higher than commercially-used seawater RO membranes, while still maintaining an 88 % ion rejection rate. On the other hand, the MIL-47(V) MOF bilayer demonstrates an impressive 97 % ion rejection rate with significantly higher water permeability (160 L/cm2/day/MPa) compared to existing membrane materials such as cellulose acetate, polysulfone aromatic polyamides, MoS2, graphene, HAB-derived MOF, and carbon nanotubes. As a result, MIL-47(V) stands out as a promising nanoporous material for advanced RO water desalination with both high water permeability and exceptional rejection efficiency. However, when the COF and MOF materials are combined in a hybrid bilayer configuration, the water permeability becomes lower than bilayers of the same material due to pore misalignment. Our findings indicate that the pore-sieving effect is the primary governing factor for the rejection in the bilayer membrane. The electrostatic interactions and hydrogen bonding formation between water molecules and the oxygen atoms in the bilayers play vital roles in regulating water transport and ion passage across the examined bilayers.

Feasibility Study of a Reverse Osmosis Desalination Unit Powered by Photovoltaic Panels for a Sustainable Water Supply in Algeria

In recent years, reverse osmosis water desalination has developed rapidly and has become the most competitive and widely used technology in the world. The number of desalination plants is increasing rapidly as freshwater needs increase. Various membrane technologies have been developed and improved, including nanofiltration (NF) and reverse osmosis (RO), whose desalination costs have been relatively reduced. Therefore, this work proposes an experimental study for a small desalination unit based on RO generated by renewable energy, which is mainly suitable for arid regions or desert areas that do not have electricity and water and can be applied for emergency treatment to meet strong freshwater resource needs. In this study, to meet the drinking water demand, a reverse osmosis desalination system is designed and evaluated in order to improve and optimize its operation. This system has a daily capacity of 2 m3. We used brackish groundwater, which has been characterized as reference water, to produce synthetic water for different salinities until seawater. The analysis is based on data obtained from experiments carried out in the standalone RO pilot designed for the production of fresh water. For this purpose, we conducted relevant experiments to examine the influence of applied pressure, salt concentration and temperature on the RO membrane performance. The effects of different factors that affect the energy consumption in the RO desalination process were analyzed, and those with significant influence were explored. The effectiveness of RO desalination coupled with a photovoltaic (PV) energy system is shown. We found the recovery rate for system operation to be 32%. An optimization study is presented for the operation of an autonomous RO desalination system powered by photovoltaic panels. The energy produced by the PV system was used to feed two pumps forthe production of drinking waterwithanRO membrane, under the conditions of the town of Bou-Ismail. As results, a 3 kWp PV system was installed based on the energy demand. The design data have shown that a 3 kWp PV system can power a 1.8 W RO load given the Bou-Ismail climate. Energy consumption in the case study under Bou-Ismail weather conditions were analyzed. The desalination of brackish water at a TDS value of 5 g/L requires an energy of about 1.5 kWh/m3. Using seawater at a TDS value of 35 g/L, this value increases to 5.6 kWh/m3. The results showed that the optimal recovery rate for system operation was determined to be 32% for a feedwater salinity of 35 g/L, and 80% for a feedwater salinity of 1 g/L.

Functionalized Carbon Honeycomb Membranes for Reverse Osmosis Water Desalination

AbstractReverse osmosis desalination is a common technique to obtain fresh water from saltwater. Conventional membranes suffer from a trade‐off between salt rejection and water permeability, raising a need for developing new classes of membranes. C‐based membranes with porous graphene and carbon nanotubes offer high salt rejection, water permeability, and fouling resistance. However, controlling the pore size of these membranes is challenging. Therefore, a carbon honeycomb membrane is studied using classical molecular dynamics simulations. It is reported that functionalization with −COO– groups provides 100% salt rejection with around 1000 times higher water permeability than conventional polyamide membranes. Atomic‐level understanding of the effect of the functional groups' location on salt rejection and water permeability is developed.

Raman spectroscopy for real-time concurrent detection of multiple scalants on RO membranes

In-situ monitoring techniques of reverse osmosis (RO) desalination systems, particularly those with chemical sensing capabilities, can provide the means for better understanding important scaling mechanisms as well as early scaling detection. In this work, both calcium sulfate and calcium carbonate scaling on RO membranes were detected concurrently in real time using Raman spectroscopy to provide a unique chemical fingerprint. Two different sampling methodologies (manual and automated) were employed, and their performance was evaluated by comparing the Raman detection times to concurrent values of flux decline. The manual sampling strategy resulted in the detection of calcium sulfate and calcium carbonate at mean permeate flux declines of 13 ± 10 % and 22 ± 3 %, respectively. The automated sampling strategy provided better performance, with detection of calcium sulfate and calcium carbonate at mean flux declines of 8 ± 5 % and 4 ± 3 %, respectively. The increased sensitivity and decreased variability of the automated sampling strategy provided valuable preliminary insights for the selection of optimized sampling strategies. The ability to identify the chemical composition of different scaling crystals including their polymorphs is an important step toward better understanding of the crystallization pathways of multi-component feed streams used in seawater and brackish water RO desalination.

Multilayer graphene oxide-based membranes for reverse osmosis water desalination: An atomistically detailed simulation study

Pressure-driven Molecular Dynamics simulations were employed to examine reverse osmosis desalination through graphene-oxide-based multilayered membranes. The effects of functionalization of the graphene-oxide flakes with poly(ethylene imine) branches in water permeability and salt rejection were described in detail. The role of the degree of structural rigidity of the membranes was also explored. A lower degree of rigidity of the membrane resulted in a 6–9 % increase in water permeability depending on the state of functionalization of the flakes. At constant membrane rigidity, functionalization of the membranes’ flakes led to approximately 30 % reduction in water permeability, but the water flux remained 2–3 orders of magnitude higher than that of conventional reverse-osmosis membranes. Moreover, functionalization of the membranes’ flakes resulted in a higher than 20 % enhancement in salt rejection at a pressure difference similar to that in actual reverse osmosis processes. Examination of the swelling behavior of the membranes showed that those based on the functionalized flakes exhibit a tendency to remain structurally coherent with an interlayer separation determined by the presence of the polymer branches. Description of the microscopic mechanisms related to the membranes’ water and ion flux, such as hydrogen bonding and concentration polarization, allowed the assessment of the contribution of different factors involved in desalination, providing new insight towards the fabrication of membranes with improved performance.

A new renewable energy based integrated gasification system for hydrogen production from plastic wastes

A multigenerational waste to energy system is developed to produce hydrogen, electricity, heating, domestic hot water, and fresh water. The proposed system utilizes plastic wastes gasification to produce syngas that is processed through multiple sub-systems. Energy and exergy analyses are comprehensively performed to study the overall system and identify the efficiencies of overall system. The system is using geothermal energy to produce steam required for plastic wastes gasification. The syngas produced by the gasification of plastic waste is processed in a combined cycle to generate power. The current system produces power at a rate of 73,550 kW. The created syngas is fed into a reforming plant, which produces hydrogen at a rate of 1.05 kg/s. A reverse osmosis water desalination sub-system is also added to produce fresh water at a rate of 12 kg/s. The developed system energy efficiency and exergy efficiency for the reference case are 66.24% and 48.10%, respectively.

Experimental Investigations and Simulation of Solar-Powered Reverse Osmosis Water Desalination System using CFD

Experimental Investigations and Simulation of Solar-Powered Reverse Osmosis Water Desalination System using CFD

Recurrent neural networks optimization of biomass-based solid oxide fuel cells combined with the hydrogen fuel electrolyzer and reverse osmosis water desalination

The current research study focuses on modeling solid oxide fuel cell (SOFC) power plants. For this purpose, in the research, three Integrated processes are presented to achieve the most optimal system from the perspective of energy and economics. An integrated SOFC is considered in the first model, the second model is focused on using the wasted heat from the first model as the entry of the Stirling engine, and in the third model, the excess energy of the Stirling engine is used to produce hydrogen with the help of proton exchange membrane electrolyze and also power generated by the first model turbine is used in desalination system to produce fresh water. Power generation and hydrogen production from the systems are considered the main two objective functions. Results show that in the presented system the most optimal state of energy efficiency is 39.6% and with an economic cost of 10.30 dollars per hour. The results also indicate that the presented energy system can produce 191 kW of output power, and 23 kg/s of hydrogen fuel with an economic cost of nearly 11 dollars/hour at its working point.

Reduction of Energy Consumption of Brackish Water Reverse Osmosis Desalination System Via Model Based Optimisation

Reverse Osmosis (RO) process is being engaged to yield fresh water from brackish water sources. However, the RO process is characterized by its high specific energy consumption (SEC) owing to high-pressure pumps. The current study focuses on reducing the SEC of the brackish water RO desalination plant using model-based optimization practice. The inlet conditions of RO process such as the feed pressure, flow rate (individual membrane module and total plant) and temperature, have a substantial influence on the performance indicators namely, water productivity, product concentration and SEC. Therefore, the optimisation of this study has been directed to determine optimal inlet conditions within feasible limits to minimise SEC. Arab Potash Company (APC) brackish water RO desalination plant has been considered as the case study. The optimal inlet conditions have resulted in a significant energy saving of 27.97% depending on the set of decision variables being considered at a fixed brackish water feed concentration.

Modeling and optimization of fuel cell systems combined with a gasifier for producing heat and electricity

In this research, a proton-conducting membrane fuel cell is used in conjunction with a gasifier for producing electricity with air considered as the gasification agent. The simultaneous electricity, heat, and hot water generation of these two when coupled with an Organic Rankine Cycle (ORC) installed within a Thermoelectric Generator (TEG) was studied. Additionally, to utilize the electricity generated from various parts of the process; i.e. the fuel cell, organic Rankine cycle turbine, and the thermoelectric generator, the reverse osmosis (OR) water desalination unit was coupled to the process. The aforementioned system was studied and analyzed based on thermodynamic and thermos-economic aspects. A parametric study was also carried out to analyze the effect of main factors on power output, energy/exergy yield, and the total cost of each system. Finally, a dual objective optimization was achieved by taking the main factors into consideration and using a genetic algorithm. Results indicated that the work generated by the system was not significant; however, the amount of hot water produced was relatively promising. Based on exergy and exergoeconomic evaluation, the After-Burner is an important non-renewable energy source while the fuel cell has a higher inefficiency cost which could be due to low work generation. Results indicate that the moisture in the biomass and the figure of merit, are important parameters that have to be kept as low as possible. The energy yield of the fuel cell was calculated to be 45.05%. Additionally, considering the optimized operating point, pure power output and system cost rate will be 1.81 KW and 5.15 $/hr respectively.

Coordinating the day-ahead operation scheduling for demand response and water desalination plants in smart grid

Integrating renewable energy resources (RES) is a challenge for power system operators due to their fluctuations and unpredictability. At the same time, the water shortage problem and the needs to desalinate more freshwater increase the prominence of sufficient energy resources for sustainable operation. Therefore, this paper presents a market-clearing mechanism in a co-optimization model that coordinates the operation of grid-connected reverse osmosis water desalination plants (RO-WDPs) and the operation of renewable-rich power systems. It is assumed that electric demands can participate in the provision of demand response (DR) to the market via multiple DR options. The DR options related to the general loads are demand shifting, load curtailment, distributed generation, and hybrid energy storage systems (HESS). These HESS includes battery storage and hydrogen storage systems. Pertaining to their special characteristics, a new DR option is proposed as a customized option for RO-WDPs. The market clearing mechanism is assumed to be based on the security-constrained unit commitment (SCUC) and formulated as a stochastic mixed-integer linear programming problem (MILP) to optimally schedule the day-ahead operation of the power system. The presented model is applied on 6-bus and IEEE 24-bus reliability test system (RTS) test power systems with significant penetration of RES to demonstrate its merits. The simulation results show that the system efficiency is enhanced by adding the energy flexibility of RO-WDP without endangering the water demand-supply when using the proposed coordinated model. Hence, the total operation cost is minimized, the RES integration is facilitated, and the hourly electricity prices are smoothened.

Modeling of Reverse Osmosis Water Desalination Powered by Photovoltaic Solar Energy

Sea water contains 35 g/L of salt, while the maximum concentration for water intended for human consumption is 400 mg/L (fresh water). Freshwater is an essential component in our daily life; but its availability is on the decline due to population growth and climate change. To meet the demand for fresh water in regions where reserves are insufficient, several countries have adopted seawater desalination. Several physical methods allow the production of fresh water from seawater, one of them being distillation and reverse osmosis, and there is great potential to use renewable energy sources such as solar photovoltaics. In order to model the phenomenon of reverse osmosis solar-based desalination, the author presents generalities of deslination technologies in the first part of this paper. The second part is devoted to the presentation of different water desalination systems combined to renewable energy, and their benefits and drawbacks from different perspectives. In the third part, the author describes the model of a PV water desalination system using Matlab Simulink software. Based on the simulation results, the author concludes this paper with the prospects of the presented work.

DEVELOPMENT OF SORPTION MATERIALS OF WIDE FUNCTIONAL PURPOSE IN THE V.I. VERNADSKII INSTITUTE OF GENERAL AND INORGANIC CHEMISTRY OF THE NAS OF UKRAINE

The review is devoted to the work, which were performed at the V.I. Vernadskii Institute of General and Inorganic Chemistry of the NAS of Ukraine according to the direction of the development of sorption naterials of wide functional purpose. All sorbents can be used in separation processes: due to their coarse dispersion and mechanical strength, they can be used as fillers for sorption columns.The direction of early works is the development of amorphous hydrophosphates and double hyd­rated oxides of multivalent metals, intended for the removal of toxic inorganic ions from water (arsenate-, chromate- and borate-anions, Cu2+, Pb2+, Cd2+cations etc.). Currently, attention is focused on the development of composite materials.The base of inorganic composites is hydrophosphate and oxide sorbents, and the modifiers are the advanced carbon materials, lithium-titanium and lithium-titanium-manganese spinels etc.Sorbents based on ion-exchange resins modified with inorganic ionites have also been developed.The combination of various components in composites makes it possible to obtain sorbents with improved properties (faster sorption, increased capacity and selectivity, sorption capacity in a wider pH range, easier regeneration) or multifunctional materials that sorb both inorganic and orga­nic compounds, for example, pesticides. Prospective field of research is the development of technologies that include not only the extraction of toxic and valuable components from liquids of natural, technological and biogenic origin, but also the regeneration of the sor­bent and processing of the concentrate to obtain commercial products.Thus, the integration of lithium sorption concentration into the process of reverse osmosis water desalination has been proposed. The processing of the solution formed during the regeneration of the sorbent includes the production of lithium carbonate and a complex fertilizer for acidic soils. Composites, the components of which are natural materials, are also in the focus of attention.Magnetic sorbents based on biopolymers, proposed for extraction of oil and oil products from water surfaces. Composites based on zeolites are used as containers for liquid fertilizers Another direction of research is the creation of composites - potential membrane modifiers for separation processes.

Analysis and simulation of reverse osmosis equipment: Case of La Guajira, Colombia

Energy resources and potable water are important assets for every country. Electric power produced from renewable sources can be used to provide water desalination systems and meet the energy needs of populations living in isolated and remote areas. This study models and simulates a reverse osmosis (RO) water desalination system using dynamic mathematical models in one dimension, and applies it to water sources from the department of La Guajira, Colombia. Most of the indigenous communities are concentrated in the upper and middle areas of that region, where there are brackish water sources such as groundwater wells that could undergo water purification to improve community’s quality of life. Furthermore, these areas have the best solar radiation potential in Colombia. The Yuyurupana indigenous community was chosen for the study; they are located in the rural area of the municipality of Maicao. This place has a groundwater well with 3055.77 mg/L of total dissolved solids (TDS) and average solar radiation of 4.8 kWh/m2/month. At a feed pressure of 11.65 atm, the system obtained a permeate concentration quality of 317.45 mg/L, which is below the maximum allowable according to the Colombian Ministry of Environment. The specific energy consumption (SEC) was calculated and yielded a value of 0.644 kWh/m3. It requires 152 photovoltaic solar panels and a total area of 294.9 m2 to supply electricity to the system. The mathematical models were validated by comparing results with those of previous studies found in the literature.

Graphene foam membranes with tunable pore size for next-generation reverse osmosis water desalination.

The development of carbon-based reverse osmosis membranes for water desalination is hindered by challenges in achieving a high pore density and controlling the pore size. We use molecular dynamics simulations to demonstrate that graphene foam membranes with a high pore density provide the possibility to tune the pore size by applying mechanical strain. As the pore size is found to be effectively reduced by a structural transformation under strain, graphene foam membranes are able to combine perfect salt rejection with unprecedented water permeability.

A Novel Hybrid Polygeneration System Based on Biomass, Wind and Solar Energy for Micro-Scale Isolated Communities

The availability of freshwater and energy is a serious issue in remote and islanded areas, especially at a small scale, where there may not be the possibility to access the grid and/or water distribution systems. In this context, polygeneration systems operating on the basis of local, renewable energy sources can be an answer to the users’ demand for electricity, heating, cooling, and domestic hot water. The scope of the proposed paper was to investigate, numerically, the energy and economic feasibility of a novel hybrid polygeneration system powered by biomass, solar, and wind energy for a micro-district of households. The proposed system consists of a biomass-fueled steam cycle, wind turbine, photovoltaic field coupled with thermal and electrical energy storage, adsorption chiller, and a reverse osmosis water desalination unit. The system is also assisted by an LPG generator set running as backup. The system provides space heating and cooling, electrical energy, and fresh and domestic hot water to 10 households located on Pantelleria Island, Italy. The proposed system is modelled and simulated through TRNSYS software with realistic user demand. The energy and economic performance of the proposed system are assessed with respect to a reference system in different scenarios, taking into account islanded operation, connection to the grid, and biomass tariffs. The results show that the proposed system achieves an excellent primary energy saving performance in all the investigated scenarios, with savings of more than 94% for all the investigated scenarios. Excluding any kind of funding, in case of new investment for the system, the simple payback oscillates between 7 and 12 years, showing that the developed alternative is fairly valid with respect to traditional solutions.