Adsorption Desalination System Research Articles

Solar-powered hybrid adsorption desalination/humidification-dehumidification system

Eco-friendly materials used in adsorption desalination system represent a good alternative to avoid the problems of pollution and global warming. Adsorption desalination technology has low relative performance and still needs more development. This work investigates novel configurations of solar-powered adsorption desalination system using composite sodium polyacrylate (SP) as adsorbent material integrated with humidification-dehumidification desalination system driven by solar energy or waste heat. Cost analysis of those novel configurations and weather effects were studied beside the performance. MATLAB and TRNSYS used hot regions' weather data to carry out the model. Sodium polyacrylate in the forms of raw sodium polyacrylate and SP/CaCl2 is used as adsorbent material. Findings reveal that for conventional solar adsorption desalination system using raw sodium polyacrylate or SP/CaCl2, the highest specific cooling power is introduced by the composite adsorbent. When utilizing raw sodium polyacrylate in the hybrid system with heat recovery, it gives relatively high values of specific daily water production, reaching 55.8 m3/ton in June, and it decreased to 41.7 m3/ton in December. Gained output ratio has been studied, and it changes from 1.73 in January to 1.58 in June and 1.75 in December. When utilizing SP/CaCl2, The hybrid system with heat recovery reached a SDWP value of 77.3 m3/ton in June, and it decreased to 51.8 m3/ton in December. Results also reveal that the SP/CaCl2 system powered by waste heat provides the cheapest desalinated water among all systems at 0.49 $/m3.

Solar-powered adsorption desalination utilizing composite silica gel with a humidification-dehumidification desalination system

This work comes in light of addressing crises of freshwater scarcity, energy demand, and climate change to investigate innovative configurations of hybrid adsorption desalination integrated with a humidification dehumidification system powered by solar energy or waste heat in four operation modes. The investigation includes economic cost analysis and system performance using raw silica gel and silica gel/CaCl2 adsorbents under the weather data of Assiut-Egypt. System performance has been evaluated regarding daily water production, gain output ratio, and cooling effect using TRNSYS and MATLAB software. The combined configuration with heat recovery (the fourth mode) using silica gel/CaCl2 gives a relatively high freshwater production (69 m3/ton.day in June) compared with the basic adsorption desalination system using raw silica gel (7.1 m3/ton.day in June). Silica gel/CaCl2 in the first mode presented the highest cooling effect (555 W/kg) in June compared with silica gel in the primary system (197 W/kg). The third configuration's solar-powered silica gel/CaCl2 system shows a clear superiority of 1.8 in gain output ratio, compared with the basic system with and without heat recovery (0.54 and 0.4, respectively). The third configuration also provided the cheapest freshwater production among all configurations at 2 $/m3 in June.

Performance analysis of a novel two-bed adsorption humidification-dehumidification desalination system using Metal-organic framework 801

Adsorption desalination techniques have been increasingly studied over the last century as a sustainable option for meeting the rapidly growing demand for fresh water. One of the attractive factors for using adsorption desalination systems is the use of low-grade thermal energy normally wasted in the atmosphere. The current study introduces a novel adsorption desalination system integrated with a humidification dehumidification system for producing potable water. Four system configurations are presented. The main distinction between them is the source of hot water used for the humidifier. Scheme #1 utilizes the heat of condensation, Scheme #2 applies the heat of condensation plus the heat of adsorption, while Scheme # 3 adds the outlet of heating water from the desorber as a source of heat to the humidifier. Scheme #4 is a standalone adsorption desalination system that applies chilled water to cool the condenser. The novelty of this system is the application of the chilled water from the evaporator to the dehumidifier to create the highest possible temperature difference necessary for the humidification and dehumidification process. This advantage allows larger water productivity, especially in hot humid regions. In this case, it is possible to extract water vapour in the ambient humid air, water vapour gained from the humidification process and water vapour condensed in the condenser of the adsorption desalination system. Moreover, we have used a novel material Metal Organic Frameworks 801 as an adsorbent for a highly efficient process. Based on the results, Scheme #3 produced the maximum amount of fresh water, 210 kg/h while Scheme #2 obtained the maximum gained output ratio, 4.4 with a minimum cost of 0.0079 $/L. A standalone adsorption system produced the minimum amount of distillate water and the lowest gained output ratio. It is not advisable to use a standalone adsorption system to produce distillate water; as the full desalination potential is not achieved.

Performance investigations of hybrid adsorption and thermo electric dehumidification desalination system

In recent years, thermally driven Adsorption Desalination Systems (ADS) have been gaining attention as an eco-friendly and energy saving solution for water scarcity. However, ADS faces challenges related to low water productivity and scalability issues associated with the adsorbent. To overcome these challenges, it is advantageous to integrate ADS with other desalination technologies, thereby creating a decentralised, small-scale hybrid desalination system. The current study introduces an innovative approach to enhance the performance of ADS by integrating it with a Thermo Electric Dehumidification (TED) unit that utilises the cold side of Thermo Electric Coolers (TECs). The proposed hybrid system is designed to operate at the elevated evaporator temperature ranges from 35 °C to 60 °C. This is achieved by connecting the hot side of the TECs to the evaporator of the ADS. This approach facilitates a fundamental shift from the conventional adsorption desalination cycle, enabling the system to work at higher evaporator temperature and pressures. A small-scale hybrid ADS integrated with a Thermo Electric Dehumidification unit (hybrid AD-TED desalination system) has been designed and developed to investigate performance parameters such as Coefficient of Performance (COP) and water productivity. Experimental study of the hybrid AD-TED system has been carried out in two operating modes: open flow and closed flow modes of water between the hot side of TEC and the evaporator. These operating modes are tested with and without implementing humidification process in the humidifier. The results have shown that the hybrid AD-TED desalination system working in open flow mode with humidification process has produced the highest water productivity of 1.25 l during one cycle of operation, lasting one hour. Furthermore, when operating in open flow mode without humidification, the hybrid AD-TED system can generate dehumidified air within a temperature range of 16–28 °C, making it suitable for cooling applications. Closed flow mode is the preferred choice for desalination applications. In the closed flow mode with and without humidification condition, the water productivity is found to be 1.15 l/hr and 1.05 l/hr, respectively. The significant feature of this hybrid AD-TED system is that it can be operated in two working modes with an elevated adsorption desalination cycle, making it a unique option compared to the single operating mode of standalone ADS in desalination and cooling applications. The study also compares the elevated adsorption desalination cycle with the conventional adsorption desalination cycle and reveals that the elevated cycle increases water uptake by 45 %.

Experimental analysis on hybrid adsorption and open air cycle humidification dehumidification (AD–OHD) desalination system

In the current status, an Adsorption Desalination System (ADS) has been found to have lower water production capacity than conventional desalination technologies. This study proposes a hybrid desalination system integrating the Adsorption (AD) and Open air cycle Humidification-Dehumidification (OHD) process to overcome the challenge of lower water production capacity in ADS. This hybrid system known as AD-OHD system comprises of a single bed ADS and a Humidification-Dehumidification (HDH) unit. The main objective of this work is to analyse the performance of the hybrid AD-OHD system based on parameters such as Gain Output Ratio (GOR) and amount of desalinated water production. The performance of the hybrid AD-OHD system is studied under three different operating conditions of switching (tswt) and sorption time (tspt), namely, tswt > tspt, tswt = tspt, and tswt < tspt. The results indicate that the optimal working condition is achieved when the hybrid AD-OHD system operates at condition tswt < tspt. The amount of desalinated water and GOR under the optimal condition is found to be 1.12 l/h and 0.78, respectively. The study also conducts experimental investigations to evaluate the GOR of the hybrid AD-OHD system under different operating conditions, including the temperature of the water entering the evaporator and the temperature of the hot and cooling water input to the adsorbent bed. Experimental data indicates a positive correlation between GOR and hot water temperatures, while increased cooling water temperature reduce GOR due to reduced adsorption behaviour. Although the evaporator inlet water temperature initially boosts GOR, it declines as the adsorption capacity diminishes. The study highlights the superior performance of the hybrid AD-OHD system compared to both the standalone single-bed ADS and open cycle HDH desalination systems. The hybrid AD-OHD desalination system exhibits an 80 % improvement over the single-bed ADS system and a 50 % improvement over the open cycle HDH system in desalinated water production. Additionally, a theoretical model of the adsorption desalination cycle is developed and validated, demonstrating the viability of the AD-OHD system for desalination applications.

Design and dynamic numerical modeling of a hybrid reverse osmosis/adsorption-based distillation system driven by solar dish Stirling engine for enhanced performance and waste heat recovery

In light of green solutions to address the shortage of freshwater shortage, energy crisis, and climate change. Tri-generation renewable systems are recently efficient approaches that can offer multiple energy outputs, such as heat, electricity, and distilled water. This paper presents a new hybrid freshwater production system driven by renewable energy for enhanced performance and waste heat recovery. This hybrid system proposes the utilization of reverse osmosis, an adsorption distillation system, and a solar dish Stirling engine (RO-ADS/SDSE). The cooperative concept is based on the re-desalination of the brine of the RO unit using an adsorption desalination system driven by the heat rejected from the SDSE, while the RO system is driven by the electrical energy produced by the Stirling engine. A mathematical model conducted in MATLAB coupled with EES package is developed to investigate the performance of the proposed RO-ADS/SDSE with and without pressure recovery (PR) mode at different salinity concentrations varying from 30000 to 50000 ppm at a constant feed pressure of 80 bar. The investigation is conducted based on the meteorological data of Tianjin, China. The results showed significant superiority in the performance of the proposed RO-ADS/SDSE system, as the annual freshwater production rate of the RO-ADS/SDSE with PR increased by up to 3000 m3 compared to 1700 m3 for the standalone RO system at a feed salinity of 45000 ppm and feed pressure of 80 bar. On a daily basis, the hourly permeating flow rate of the RO-ADS/SDSE with PR increased from 2.30 m3/h to 2.60 m3/h, and the permeate salinity decreased from 190 to 120 ppm. While the daily electricity consumption decreased from 5.20 to 4.40 kWh/m3. In conclusion, the proposed RO-ADS/SDSE system with PR can be considered a promising approach in maximizing the performance of desalination systems.

Development and assessment of a novel integrated system powered by parabolic trough collectors for combined power, heating and freshwater production

Abstract Hybrid solar-based integrated systems represent a viable solution for countries with abundant solar radiation, as they provide energy needs in an environmentally friendly way, offering a sustainable and economically advantageous energy solution that utilizes a free source of energy. Therefore, this research offers a thermodynamic evaluation of a novel integrated system driven by solar energy that aims to produce power, heating and freshwater. The integrated system consists of a parabolic trough collector that uses CO2 as its working fluid and implements the supercritical carbon dioxide cycle to generate power and heating. The integrated system also includes an adsorption desalination system with heat recovery between the condenser and evaporator, which employs a cutting-edge material called an aluminium fumarate metal–organic framework to produce fresh water. For the modelling of a novel system, an engineering equation solver, which is considered a reliable tool for thermodynamic investigations, is employed. The effectiveness of an integrated system is evaluated using a mathematical model and different varying parameters are examined to ascertain their influence on thermal and exergy efficiency, specific daily water production and gained output ratio. The results revealed that the parabolic trough collector achieved a thermal efficiency of 67.2% and an exergy efficiency of 41.2% under certain conditions. Additionally, the thermal efficiencies for electrical and heating were obtained 24.68% and 9.85%, respectively. Finally, the specific daily water production was calculated, showing promising results and an increase from 7.1 to 12.5 m3/ton/day, while the gain output ratio increased from 0.395 to 0.62 when the temperature of hot water increased from 65°C to 85°C, under the selected conditions.

Analysis of solar-powered adsorption desalination systems: Current research trends, developments, and future perspectives

Growing population increases freshwater demand for all vital activities: industrial, agricultural, and drinking; thereby, desalination capacity has grown significantly. The development of new adsorption desalination technologies has been getting much attention recently. These systems can be driven by low-grade heat sources such as solar energy, using environmentally friendly working fluids to generate potable water. The present study conducted a bibliometric analysis to identify current trends, developments, and future perspectives in adsorption desalination systems based on the publications between 2011 and 2022. The analysis covers seven major research indicators: annual publication trends, major contributing countries, scientific mapping of research sources, analysis of keywords, highly cited papers, most contributing institutions and authors, and research gaps. The paper additionally characterized the yearly publication trends, emphasized significant phrases such as water filtration, evaporation, and environmental impact. Also identified major contributing countries such as China, Egypt, Saudi Arabia, India, and United Kingdom. Among the notable institutions mentioned are Sohag University, Ministry of Education in China, King Abdullah University. Finally, the analysis provided an outlook on future research directions, including investigating novel membranes and adsorbents, investigating hybrid desalination systems integrated with nanomaterials, and using energy and cost analysis modeling and optimization techniques.

Weather effect and cost analysis of solar adsorption desalination system using MIL-101(cr) – Graphite oxide composite material

Solar-powered adsorption desalination systems (ADSs) are a significant way to provide clean and fresh water using environmentally friendly adsorbent materials. This work presents an innovative investigation of solar-driven ADS's performance and cost analysis using a metal–organic framework MIL-101(cr) with and without a 2D graphite oxide (GO) material. The investigation is conducted over a complete year using lumped modeling by MATLAB and TRNSYS software. The production cost of desalinated water is evaluated using solar energy and waste heat sources. It is found that the effect of adding 2D-GO to MIL-101(cr) is positive on the isotherms and negative on the kinetics properties; hence the overall performance of MIL-101(cr) and MIL-101(cr) + GO was very close with an average difference of 2%. Optimum-specific daily water production and gain output ratio achieved at summer 24 m3/ton-day and 0.7, respectively, using MIL-101(cr). The cost is estimated to be 4.7 $/m3 using solar energy and 1.01 $/m3 using waste heat. The performance parameters indicate the effectiveness of MIL-101(cr) in solar/waste heat-driven ADS at a reasonable cost to remote areas.

Evaluation of an innovative polygeneration system based on integration of gasification process with a thermo electric generator- solid oxide fuel cell - Adsorption desalination system - Thermal photovoltaic collector

The current study is conducted to propose a polygeneration system for producing electricity, potable water, cooling, hot domestic water, hydrogen, oxygen, and nitrogen. The proposed system is fueled by heavy oil, natural gas, and solar radiation. Accordingly, the integration of an air separation unit, gasifier, gas turbine cycle, steam Rankine cycle, organic Rankine cycle combined by ejector refrigeration cycle, solid oxide fuel cell, thermoelectric generator, proton exchange membrane electrolysis, adsorption desalination, concentrated photovoltaic thermal collector and CO2 capture are done. The energy, exergy, exergoeconomic, exergoenvironmental, emergoeconomic, and emergoenvironmental analyses have been done to evaluate and compare different aspects of the system. With this, it becomes possible to move towards sustainable development by considering different aspects of the problem. For better performance of the system, multi-objective optimization was done using artificial intelligence. In this optimization, the decision variables were selected as a result of a comprehensive sensitivity analysis. As a result of this optimization the exergy efficiency of the system, LCOE, LEIOE, the emergy rate of the system, and the flow of produced hydrogen are 18.51%, 142.94$/MWh, 330.77Pts/MWh, 14443.28 × 1011 sej/s, 101.88 kg/h. The net power production of the system is 427.98 MW while the hydrogen cost is 19.56/GJ.

Novel proposal and assessment of a solar-powered supercritical CO2 cycle integrated with adsorption desalination system for electricity, heating and desalination

This paper presents a thermodynamic performance evaluation of a novel solar based supercritical CO2 (S-CO2) cycle and low temperature adsorption desalination (AD) cycle for power, heating, and freshwater. This novel technology utilizes molten salt as a medium for thermal energy transfer in the solar tower collector and generates power and heating by utilizing the S-CO2 cycle, as well as the AD cycle with heat recovery using aluminium fumarate material to produce freshwater. A parametric investigation is established in order to numerically assess the influence of different parameters on the performance parameters of the novel proposed system. Results show that the thermal efficiency of the solar tower receiver improves from 89.12% to 90.53%, when DNI rises from 900 W/m2 to 1100 W/m2. The thermal and exergy efficiencies of the S-CO2 power cycle are found to be higher at 1100 W/m2 and it is ranged from 33.4% to 44.81% and 54.2%–72.52% respectively, with the rise in inlet pressure of the expander from 12000 kPa to 18000 kPa. In addition, the thermal efficiency of electrical and heating was obtained 25.33% and 10.13%, respectively, at operating conditions. The highest SDWP was achieved 12.5 m3/ton/day and 0.62 GOR at a fixed operating condition.

Cost analysis and performance investigation of solar-powered desalination system utilizing modified sodium polyacrylate adsorbent material

Seawater has been desalinated using various processes at different techniques, most of which depend on fossil fuels. On the contrary, there is a need for environmentally benign desalination systems. Adsorption desalination system (ADS) is one of these systems thatemploy eco-friendly materials to reduce environmental pollution and global warming. This paper examines the performance metrics of promising materials used in ADS to lower desalinated water prices. This research uses sodium polyacrylate (SP), special SP/(NH4)2CO3 activated materials, and SP/CaCl2 composite to theoretically examine ADS's performance and cost analysis. Also, ADS performance with and without heat recovery (HR) is compared. Using tools from MATLAB and TRNSYS, the model is carried out over a year using live weather data from hot regions. Results show that the SP/CaCl2 composite has a relatively high specific daily water production (SDWP) of 15 m3/ton with COP = 0.67. The SDWP can be increased up to 45 m3/ton if heat recovery is used in the system. The cost of desalinated water is estimated at 3.8 $/m3 using Solar energy and 0.63 $/m3 using waste heat evaluated for a system with HR.

Improved adsorption desalination performance of DUT-67 by incorporating Graphene Oxide (GO)

Metal-organic frameworks (MOFs) have been recognized as one of the most promising adsorbents for adsorption desalination system (ADs) owing to their ultrahigh surface area. DUT-67 is a water-stable MOF with superior adsorption capacity, which has been demonstrated as a potential candidate for ADs. To further improve its desalination performance, in this work, different amounts of graphene oxide (GO) was incorporated with DUT-67 to obtain DUT-67/GO composites. The adsorption desalination performance including specific daily water production (SDWP) and performance ratio (PR) of DUT-67/GO composites under varying operating conditions were estimated by a lumped-parameter model. It is found that the mesopores in DUT-67/GO composites are favorable for the mass transfer. Among various DUT-67/GO composites, the DUT-67/GO composite with 24 wt% GO addition (DG-24) exhibited the highest water uptake (0.34 g/g) and overall mass transfer coefficient (0.0019 s−1), which were increased by 12.4% and 15.1% compared to DUT-67. Moreover, the average SDWP (14.7 m3/(ton/day)) and PR (0.77) of DG-24 were significantly improved by numerical simulation compared with DUT-67 (SDWP = 12.8 m3/(ton/day), PR = 0.72), which can be ascribed to their increased pore size and mass transfer coefficient.

Performance evaluation of a novel integrated adsorption desalination system with direct contact membrane distillation plant

Since adsorption desalination (AD) technology has low performance, a hybrid adsorption desalination system with a direct contact membrane distillation plant (AD-DCMD) is proposed for enhanced water production and reduced water cost. In addition to the desalination process, the cooling effect is also produced as a by-product of air conditioning. Two AD-DCMD configurations are investigated, in which the heat released from the AD condenser (configuration 1) and the adsorption process (configuration 2) are utilized to drive the DCMD system. The main performance parameters, such as gain output ratio (GOR), specific daily water production (SDWP), freshwater cost, and coefficient of performance (COP), are investigated. The influential operating parameters are tuned to obtain optimal performance. Results show that GOR values reach 1.48 and 1.6 for configurations 1 and 2, respectively, which is more than the AD system by >117 %. For configuration 2, the SDWP reaches 53 m3/ton per day, higher than the AD system by 136.7 %, at an operating temperature of 90°C. COP was found to be 0.76 and 0.70 for configurations 1 and 2, respectively. Moreover, the freshwater cost of configurations 1 and 2 is 1.72 and 0.92 $/m3, with a reduction of 18.03 and 56.05 %, respectively, compared to the AD system.

Performance analysis of a lab-scale adsorption desalination system using silica gel/LiCl composite

Adsorption desalination is a novel technology to supply high-quality potable water driven by a low-temperature heat source. However, only a few composite sorbents, whose excellent performances have been demonstrated in other adsorption-based systems, have been applied in adsorption desalination (AD) systems. This study evaluated the performances of LiCl-silica gel (30 % wt) composite in a lab-scale AD system, realized by packing the sorbents beads inside a finned flat-tube heat exchanger. For the first time, the ad/desorption dynamics under various operating conditions were measured using a T-LTJ (thermal-large temperature jump) apparatus, which has not been employed for evaluation of desalination prototypes so far. The sorption dynamics was compared with silica gel, which is a standard material for AD systems. Results were used to calculate the maximum specific daily water production (SDWP) and optimized cycle time. Moreover, three design strategies of the AD system were proposed, including 2-beds, 3-beds and 4-beds. The 3-beds-configuration was selected for the composite sorbent, being able to reach an SDWP as high as 69 m3/tonne/day under the condition of Teva/cond = 20 °C and Tde = 80 °C. The optimized cycle time is dependent on operating conditions, varying in the range of 240–470 s.

Recent development in adsorption desalination: A state of the art review

Adsorption desalination is prescribed as a promising and eco-friendly solution for mitigating water scarcity, owing to its utilization of low-grade thermal waste and zero liquid brine discharge. The keystones that regulate the performance of the adsorption desalination system (ADS) include nature of adsorbents, system design, and operating conditions. The present study aims to provide a state of the art review on the keystones of ADS. Metal-organic frameworks (MOFs) hold remarkable adsorption capacity and tunable structure. However, hydrothermal instability, high cost, and complex synthesizing procedures are the potential challenges that need to be addressed. The technological advancements in ADS have been classified into: (i) Conventional Approach, (ii) Heat and Mass Recovery Approaches, (iii) Hybridization Approaches, (iv) and Adsorbent Substituting Approach. The study provides critical insight and compares the performance of each approach based on specific daily water production (SDWP), specific cooling power (SCP), and coefficient of performance (COP). The conventional ADS produce SDWP of 4.7 m3/ton/d, however producing zero and/or minimal SCP while using payable energy of 1.50 kWh/m3. In heat/mass recovery approaches, pressure equalization-valve delay schemes and master–slave configuration provide ∼ 5 % additional water adsorption/desorption on/from silica-gel and reduce ∼ 50 % thermal heating load, respectively. Evaporator-condenser amalgamation emphasizes the evaporator temperature of 30–42 °C leading towards ∼ 69 % higher SDWP with zero SCP. Dual stage, multi evaporators/condensers scheme is found supportive in cogenerating feature of ADS thereby improvising COP to ∼ 0.87. In hybridization approach, ejector integrated ADS produces SDWP of 80 m3/ton and COP of 2.22 using payable energy of 0.92 kWh/m3, however, needs experimental validation. In the adsorbent substituting approach, CPO-27(Ni), Emim-Ac/Syloid 72FP, and composite adsorbent manifest the SDWP to higher levels. The operating conditions are sensitive and need to optimize depending on the configuration of ADS. Possible future research directions may include efficient designing/ sizing of evaporators/ condensers, minimizing the heat and mass transfer resistances in adsorber/desorber reactor, optimize the thickness of the adsorbent layer in heat exchangers, and investigating wide range of adsorbent classes that can be driven with very low regeneration temperature.

Operating Temperatures Effect on Adsorption Desalination System Powered by Solar Energy

Operating Temperatures Effect on Adsorption Desalination System Powered by Solar Energy

Characterization and cost analysis of a modified silica gel-based adsorption desalination application

This study aims to reduce adsorption desalinated water cost by innovative employing silica gel/CaCl2 composite and novel silica gel/(NH4)2CO3 activated materials. Raw silica gel (SG), which served as the host matrix, was acid-treated and impregnated with CaCl2 and (NH4)2CO3. The prepared samples characteristics (XRD, N2 adsorption, water vapor adsorption) have been investigated and compared to the raw SG. A simulation model has been used to investigate the impact of the study samples on adsorption desalination (AD) system performance with and without heat recovery (HR). The study also includes a cost analysis of the AD water production system (using the tested materials) that uses solar energy or a waste heat source. The SG/CaCl2 achieved the highest water adsorption (0.95 kgH2O/kg) with a SDWP of 23.3 m3/ton per day, SCP 660 W/kg, and COP 0.71. With HR, the system could produce 35 m3/ton of SG/CaCl2 per day SDWP. The study concluded that the tested samples outperform the raw material as the total production cost of AD water using SG/CaCl2 has been reduced to approximately 37% using solar energy and 60% using waste heat as a regenerative heat source.

Theoretical evaluation of adsorption desalination performance of metal-organic frameworks under varying scenarios

• Adsorption desalination performance of 12 adsorbents was evaluated. • MOFs outperform other adsorbents owing to their higher water transfer amount. • Desalination performance of adsorbents is correlated with adsorption characteristics. • DUT-67 is the most potential candidate under varying operation conditions. Adsorption desalination systems (ADs) driven by low-grade energy are regarded as sustainable alternatives to address water shortages due to their low energy consumption. Adsorbents is the key materials for the performance of ADs. In this work, a numerical study was performed to assess the water production performance of ADs based on metal–organic frameworks (MOFs) and other adsorbents under different working conditions. It is found that the trends in specific daily water production (SDWP) and performance ratio (PR) with hot and chilled water temperature are closely correlated with the adsorption characteristics, i.e., water uptake and the shape of adsorption isotherms. Moreover, considering both SDWP and PR, MOFs outperform other adsorbents owing to their high water transfer amount per cycle under various conditions. Among 12 adsorbents, DUT-67, Al-fumarate and MIL-100(Fe) are the top performers at chilled water temperature of 10 °C, 20 °C and 30 °C respectively with average SDWP (PR) of 3.31 m 3 /ton/day (0.33), 8.05 m 3 /ton/day (0.56) and 13.46 m 3 /ton/day (0.71), increased by 43.8% (32.0%), 65.3% (40%), and 102.7% (44%) compared to traditional silica gel. This work provides helpful insights into the correlation between desalination performance and water adsorption characteristics of adsorbents under varying working conditions, which favors choosing and designing of potential adsorbents for ADs.

Composite material-based a clay for adsorption desalination and cooling applications

This paper studies improving the performance of an adsorption system by improving raw bentonite as an adsorbent. Acid treatment has been used for the pretreatment of raw bentonite. Then, a composite and activated adsorbents are prepared by bentonite impregnated in salt hydrates (CaCl2 and (NH4)2CO3). XRD, nitrogen adsorption isotherm, water vapor adsorption isotherm and kinetics are used to characterize raw and modified bentonite. Experimental results of adsorption isotherms and kinetics have been fitted using Dubinin–Astakhov equilibrium model and linear driving force model. MATLAB software has been used to solve a simulation model of an adsorption desalination system with and without heat recovery (HR). The effect of the modified adsorbents on the adsorption system performance has been investigated. The results illustrated that the surface area and pore volume of Bent/CaCl2 increased by about 200% and 500%, respectively, compared to raw bentonite. The Bent/CaCl2 was predicted to have the highest water uptake (0.82 kgH2O.kg−1). Bent/CaCl2 was predicted to have a SDWP of 11.5 m3.ton−1 per day with SCP 326 W.kg−1 and COP 0.52 at 85 °C desorption temperature. Also, the SDWP was predicted to achieve 26 m3.ton−1 per day with HR under the same conditions. The SDWP can be increased to 29 m3.ton−1 at 95 °C desorption temperature.