Water Purification System Research Articles

Thiacalixarenes with Sulfur Functionalities at Lower Rim: Heavy Metal Ion Binding in Solution and 2D-Confined Space.

Sulfur-containing groups preorganized on macrocyclic scaffolds are well suited for liquid-phase complexation of soft metal ions; however, their binding potential was not extensively studied at the air–water interface, and the effect of thioether topology on metal ion binding mechanisms under various conditions was not considered. Herein, we report the interface receptor characteristics of topologically varied thiacalixarene thioethers (linear bis-(methylthio)ethoxy derivative L2, O2S2-thiacrown-ether L3, and O2S2-bridged thiacalixtube L4). The study was conducted in bulk liquid phase and Langmuir monolayers. For all compounds, the highest liquid-phase extraction selectivity was revealed for Ag+ and Hg2+ ions vs. other soft metal ions. In thioether L2 and thiacalixtube L4, metal ion binding was evidenced by a blue shift of the band at 303 nm (for Ag+ species) and the appearance of ligand-to-metal charge transfer bands at 330–340 nm (for Hg2+ species). Theoretical calculations for thioether L2 and its Ag and Hg complexes are consistent with experimental data of UV/Vis, nuclear magnetic resonance (NMR) spectroscopy, and single-crystal X-ray diffractometry of Ag–thioether L2 complexes and Hg–thiacalixtube L4 complex for the case of coordination around the metal center involving two alkyl sulfide groups (Hg2+) or sulfur atoms on the lower rim and bridging unit (Ag+). In thiacrown L3, Ag and Hg binding by alkyl sulfide groups was suggested from changes in NMR spectra upon the addition of corresponding salts. In spite of the low ability of the thioethers to form stable Langmuir monolayers on deionized water, one might argue that the monolayers significantly expand in the presence of Hg salts in the water subphase. Hg2+ ion uptake by the Langmuir–Blodgett (LB) films of ligand L3 was proved by X-ray photoelectron spectroscopy (XPS). Together, these results demonstrate the potential of sulfide groups on the calixarene platform as receptor unit towards Hg2+ ions, which could be useful in the development of Hg2+-selective water purification systems or thin-film sensor devices.

Supramolecular Nanohelix Fabricated by Pillararene-Based Host–Guest System for Chirality Amplification, Transfer, and Circularly Polarized Luminescence in Water

Supramolecular Nanohelix Fabricated by Pillararene-Based Host–Guest System for Chirality Amplification, Transfer, and Circularly Polarized Luminescence in Water

Super Water‐Extracting Gels for Solar‐Powered Volatile Organic Compounds Management in the Hydrological Cycle

Water-soluble volatile organic compounds (VOCs) are widely spread in the natural hydrological cycle, contaminating potential water sources, and leading to unexpected ecological hazards. However, water-purification technologies toward VOCs are energy-intensive and present unsatisfactory purity of the obtained water. The fundamental challenge is to differentiate the motion of water and VOC molecules by separators. Here, the concept of a super water-extracting gel (SWEG) for VOC-management and water purification via direct solar distillation is proposed. The strong hydrogen bonding effect in the hypercrosslinked hydrophilic polymeric networks enables the SWEG to extract water from VOC-containing water, which rejects the VOC solutes while allowing water through for interfacial evaporation. The obtained SWEG achieves a VOCs removal ratio up to 99.99% by solar distillation under 1 sun. A solar water-purification system is also demonstrated to produce clean water, which surpasses other competitive technologies based on electricity.

Water-pumping and purifying hydrogels driven by diurnal temperature variation

Diurnal temperature variation is an untapped energy source, although it has seldom been exploited as such. In this study, a novel system of thermo-responsive hydrogels uses diurnal temperature variation as the only power source to pump and purify water. Water is pumped at night and released during the day using an anisotropic xylem-mimetic structure whose composite phase functions as a water channel valve. The water-pumping efficiency ranges from 78% to 92%, and the weights of the pumped water per cycle are 2–3 times larger than those of the pumping materials. The anisotropic structure and the hydrophobic silicone phase are critical in determining pumping efficiency, which allow irreversible water flow upon temperature variation. Seasonal and regional temperature changes can be matched using thermo-responsive hydrogels with different volume transition temperatures. Purification of dye-contaminated water and separation of oil–water mixtures are also successfully achieved based on the hydrophilic and the pollutant-adsorbing nature of hydrogels. Since temperature changes even faster than the diurnal temperature cycle can also power this water pumping and purification system, this novel mechanism could provide a new operational solution for future water management.

Waste Egg Tray and Toner-Derived Highly Efficient 3D Solar Evaporator for Freshwater Generation.

With the advancement of civilization, water purification, as well as management and disposal of ever-increasing municipal solid waste (MSW), and e-waste, have become global concerns. To address these issues in a sustainable way, a 3D solar evaporator has been proposed in this paper by repurposing recycled paper from MSW in the form of egg trays and waste dry toner (e-waste) using a facile fabrication method. The unique 3D porous structure, fibrous surface, superior water absorbing capability as well as low thermal conductivity of wastepaper-derived egg trays make them an excellent candidate for an efficient solar evaporator, while the waste toner powder coating significantly enhances the optical absorbance capacity. Under 1 sun illumination, the proposed solar evaporator demonstrates an excellent evaporation rate and efficiency of 1.3 kg/m2 h and 78.5%, respectively. Moreover, the competitive advantage of the 3D structure in collecting solar irradiance at various light incident angles in comparison to a 2D structure, excellent cycle stability, low processing temperature, and the use of low-cost waste materials enable its use for large-scale water purification systems.

Natural Porous Materials for Interfacial Solar Steam Generation toward Clean Water Production

The progression of photothermal materials with broad solar absorption and improved photothermal conversion efficiency is critical for developing interfacial solar steam generation (ISSG)‐based water desalination and purification systems. This green solar‐driven water vaporization technology has regained popularity as a sustainable solution to water shortage. Among many other photothermal materials, natural porous material‐based photothermal evaporators have piqued the interest of researchers owing to their biodegradability, abundance, low thermal conductivity, low cost, natural capillary mechanism, and hydrophilicity. In this review, recent advances in photothermal material design based on various natural porous materials are reported, systems considering contact mode and the water transportation route are categorized, optical absorbance is assessed, and thermal management issues and water purification as well as desalination applications are discussed. This review stimulates further investigation and research interest in the utilization of natural porous materials for large‐scale ISSG‐based application implementation.

Toward a Feasible Solution for Removing Toxic Mercury and Chromium From Water Using Copper Oxide Nanoparticles

Objective: Water contaminated with heavy metals causes serious environmental issues for people. Mercury and chromium are considered to be extremely toxic for public health. Diversified technologies have been introduced to purify contaminated water; however, only a few become successful in reducing mercury and chromium below the permissible limit of drinking water (0.001 and 0.05 ppm, respectively, WHO/BIS Guidelines). Our main aim was to synthesize suitable nanoscale materials to make water potable by removing mercury and chromium from contaminated water while keeping essential elements as per the WHO/BIS guidelines.Methods: Copper(II) oxide nanomaterials are synthesized following a wet chemical process as per earlier reported procedures. Nanoparticles with average diameter of 10–20 nm are formed. XRD confirms the formation of orthorhombic CuO nanoparticles.Results: The nanoparticles are efficient in removing mercury from 200 ppb to less than 50 ppb (75%) and chromium from 200 ppb to less than 16 ppb (92%) over a wide range of pH.Conclusion: The nanomaterials have great potential in removing toxic heavy metals from contaminated water. The materials can be applied to integrated water purification systems to produce potable water.

A review of MXenes as emergent materials for dye removal from wastewater

MXenes have emerged as a superlative contestant water purification technology due to their two-dimensional multilayered structures, multifarious chemical composition, photocatalytic properties, and activated metallic hydroxide sites. The explosion of publications on MXenes results in (≥4380 articles) with the title ‘’MXenes’’ according to the Web of Science (as of Nov. 16th, 2021), so it is essential to provide timely updates of this field with particular emphasis on MXenes in dye removal/degradation/adsorption that is rarely reported. This review emphasizes the rational design of MXenes-based composites, membranes, sorbents, photo-catalysts, and electrodes for dyes removal/adsorption/degradation supported by several mechanisms. The comparison between MXenes and other materials is also highlighted for the sustainable development of the water purification system along with the life cycle assessment of MXenes and their cytotoxicity and potential for large-scale applications. However, there are current challenges and prospects on MXenes that must be mitigated to endorse their practical utilization in sustainable future societies.

Studying waters of the Volgo-Don canal for the purpose of irrigation

The data on the quality of water for irrigation and measures to improve the uniformity of distribution of artificial rain along the water pipeline of the sprinkler in order to increase the quality of irrigation are given. It has been established that the uniformity of irrigation is affected by the quality of water, in particular the presence of small particles and impurities in it, which clog the sprinklers, leading to the cessation of water supply to the irrigated area. Plants do not get enough moisture, resulting in lower yields. Studies on the uniformity of the distribution of the rain layer when irrigating with the Don-K sprinkler showed that after the installation of a water purification system in front of the water pipeline input, a more uniform distribution of rain was observed along the water-conducting belt of the farm. The content of undissolved impurities decreased by a factor of 10, and the irrigation rate increased by 15%.

New Efficient Configurations for Sour Wastewater Treatment

Background: The environmental legislation on pollutant concentrations in aqueous effluents tends to tighten and increase due to the huge efforts devoted as a response to global warming and its related negative impact on our planet. As a result, sour water must be handled and processed properly to provide a high quality of stripped water with insignificant traces of NH3 and H2S. This approach must be achieved within the minimum operating costs. This scientific research investigates the stripping configurations of sour water effluents from various industries. The research also offers an insight into different scenarios and configurations to accomplish set targets satisfying the environmental law criteria. Methods: This research introduces a range of heat integration schemes for saving energy. Further, vapor recompression “VRC” technique is opted for its ability to maximize energy savings. This research also investigates the effect of operating and design variables on the stripped water quality, such as feed temperature, feed location, reflux split, and steam flow rate. The option of adding new equipment is also addressed to maximize heat integration and enhance the efficiency of the process. Thus, several schemes and process configurations are explored to treat the industrial sour water waste streams seeking better efficiency. Those configurations differ from one another in heat integration layout and VRC utilization. The energy efficiency and economics of the proposed configurations are considered decisive factors in this research study. The case study adopted in this research is based on published data taken from several iron and steel factories in South Korea named POSCO (Pohang Iron and Steel Corporation). Results: The obtained results of the treated wastewater streams guarantee that the effluent sour water obeys the standard environmental regulations, i.e., NH3 contents range from 30 to 80 ppm and H2S concentration falls below 0.1 ppm. The obtained results of the seven different scenarios are compared to the original case study. It is found that scenario 7 is the most economical solution saving 51.54 % of the total annual cost compared to the original case study while satisfying the treated water environmental regulations with a concentration of 3.19 ppm NH3 and 0.05 ppm H2S. Scenario 7 creates its own steam, unlike the original case study where steam utility is needed extensively. However, scenario 7 consumes 15 % more electricity than the original case study, but it also still shows 56.34 % less than the overall utility cost. Conclusion: The optimum process configuration can be employed for other sour water purification systems such as those used in petroleum refiners. An ongoing research work focuses on the use of internal heat integration for more energy savings and economic improvement.

Algal treatment of membrane rejects: a unique approach towards zero liquid discharge

A major concern in membrane-based water purification system is generation of huge concentrate stream and wastage of water. A typical Reverse osmosis (RO) or Nanofiltration (NF) system generates 20–25% reject containing high amount of dissolved salts and other contaminants. Contrary to popular belief, this reject water cannot be used without removing the contaminants or cannot be discharged anywhere. Main goal of this project is to find a cheapest and green way for treatment of RO/NF reject. Algal evaporation technique was explored in laboratory scale, to find its suitability for treatment of chloride-rich membrane reject in actual scenario and based on the results obtained, a pilot plant of 48KL was established on Hooghly Met Coke division (HMC), Tata Steel. Particular species of microalgae was selected, to take up minerals from reject water. There are several types of bacteria and symbiotic algae associated with selected micro algae survive in high TDS. A unique slope roof system, connected with algae growth tank, helps in efficient evaporation of water ensuring a Zero discharge. A markedly improved performance was achieved when algal evaporation followed solar evaporation. A total evaporation of 11 L/m2/day was observed, which was almost five times faster than Solar evaporation.

Bactericidal efficacy of non-thermal plasma activation against Aeromonas hydrophila and immunological responses of koi (Cyprinus carpio haematopterus)

In the aquaculture industry, an efficient and safe water purification system is important to prevent mass mortality by virulent pathogens. As extensive use of traditional methods (e.g.: povidone-iodine, ozone, ultraviolet irradiation, formalin, and chlorine dioxide) have adverse effects on cultured fish, an appropriate and alternative water purification method is vital for the sustainability of the industry. Non-thermal plasma technology has been successfully used for various biomedical purposes (e.g: food sterilization, medical device disinfection, wound healing, cancer therapy, etc.) and has great potential to be used as a sterilizing system. However, few studies have been conducted on its usefulness in the aquaculture industry. In this study, we investigated the bactericidal efficacy of plasma-activated water induced by non-thermal plasma and its histopathological as well as immunological adverse effects on koi. A highly virulent Aeromonas hydrophila SNU HS7, which caused massive mortality of koi, was used for this study. Non-thermal plasma was applied for 10 min to the fish tanks with 1.2 × 109 CFU/mL SNU HS7 using PLMB-20 system to confirm the sterilization efficacy and to observe the survival and immunological reaction of koi for 14 days. As a result, gross pathological, histopathological, and immunological investigations did not reveal any significant adverse effects in fish as compared to the control groups. To the best of our knowledge, this is the first study showing that non-thermal plasma can be used for sterilization of rearing water without giving significant physiological damage to the fish, even under the assumption of extreme situations. As plasma can effectively sterilize not only bacteria but also other unknown pathogens, the results of this study are showing a promising future in purifying water in aquaculture practice.

Photothermal Diatomite/Carbon Nanotube Combined Aerogel for High‐Efficiency Solar Steam Generation and Wastewater Purification

Solar‐driven interface evaporation is a sustainable and green method for seawater desalination and wastewater purification which has attracted great attention due to the expectation to solve the global fresh water crisis. Currently, its commercial application is still limited by high cost, a complicated preparation process, and unsatisfying photothermal conversion efficiency, which are difficult to be achieved simultaneously. Herein, a nontoxic, high efficient, low cost, and facile strategy to fabricate a solar steam generator is demonstraterd, in which biocompatible agar powder, carbon nanotubes, and diatomite are combined to achieve an aerogel. All materials involved are commercially available. The aerogel exhibits a water evaporation rate of 1.67 kg m−2 h−1 with 91% conversion efficiency under one sun illumination, and can produce drinkable water from sea water, lake water, and even strong acid/alkaline water with nearly 100% rejection of organic dyes. Most importantly, the cost to produce such an aerogel is only 6.67 $ m−2, and is expected to produce 5–8 kg m−2 of fresh water per day under natural sunlight, which is enough for a family of three to live normally for one day. Present high‐efficient and economic water purification system provides promise for commercial application in seawater desalination and wastewater purification.

Nature-inspired poly(N-phenylglycine)/wood solar evaporation system for high-efficiency desalination and water purification

The development of low-cost, scalable wood-based photothermal systems that utilize renewable solar energy for energy conservation and desalination has received extensive attention. Although some materials such as precious metals, semiconductor materials and carbon nanomaterials have been used as light absorbers, the issues of low evaporation rate and efficiency, as well as the high energy consumption and cost of photothermal layer design need to be addressed. In this work, inspired by the transpiration process of trees, a poly(N-phenylglycine) (PNPG)-wood solar evaporator was developed. The coating of PNPG, a conjugated polymer with good light absorption, greatly cover the shortage of weak light absorbance of wood, and effectively improved the solar-heat conversion efficiency. Moreover, benefited from the low thermal conductivity and special microstructure of the wood, the relationship among water transport, solar energy conversion, and heat regulation was better adjusted. As a result, the PNPG-wood system can effectively and quickly generate steam, the evaporation rate and efficiency can be 1.64 kg m–2 h–1 and 90.4% under 1 sun, which are higher than most reported wood-based solar evaporators. Hence, such a well-designed, cost-effective, durable, and high-efficiency solar evaporation system has the potential to be applied to solve the practical problem of seawater desalination and water purification.

Single-atom catalysts based on Fenton-like/peroxymonosulfate system for water purification: design and synthesis principle, performance regulation and catalytic mechanism.

Novel single-atom catalysts (SACs) have become the frontier materials in the field of environmental remediation, especially wastewater purification because of their nearly 100% ultra-high atomic utilization and excellent properties. SACs can be used in Fenton-like catalytic reactions to activate various peroxides (such as hydrogen peroxide (H2O2), ozone (O3), and persulfate (PSs)) to release active radicals and non-radicals, acting on target pollutants, and realize their decomposition and mineralization. Among them, peroxymonosulfate (PMS) in PS systems has gradually become an important oxidant in Fenton-like processes due to its asymmetric molecular structure and characteristics of easy storage and transportation. Focusing on the numerous proposed strategies for the synthesis and performance regulation of Fenton-like SACs, it has been confirmed that the coordination of isolated metal atoms and the support/carrier enhances the structural robustness and chemical stability of these catalysts and optimizes their catalytic activity and kinetics. Moreover, the tunability of the coordination environment and electronic properties of SACs can improve their other catalytic properties, such as cycle stability and selectivity. Thus, to systematically explain the relationship between the active center, catalyst performance and the corresponding potential catalytic mechanism, herein, we focus on the representative scientific work on the preparation strategy, catalytic application and performance regulation of Fenton-like SACs. Specifically, we review the typical Fenton-like SAC reaction processes and catalytic mechanisms for the degradation of refractory organic compounds in advanced oxidation processes (AOPs). Finally, the future development and challenges of Fenton-like SACs are presented.

Application of HACCP for development of quality risk management in a water purification system

The present work reports the implementation of the Hazard Analysis Critical Control Point (HACCP) methodology to analyze the water purification system of a pharmaceutical site, in order to assure the system quality and prevent failures. As a matter of fact, the use of HACCP for development and implementation of Quality Risk Management (QRM) is not usual in pharmaceutical plants and it is applied here to improve the performance of the water purification system of a polymerization pilot plant used to manufacture pharmaceutical grade polymer microparticles. Critical Control Points (CCP) were determined with the aid of a decision tree and questions were made to characterize whether identified hazards constitute actual CCPs and should be monitored. When deviations were detected, corrective actions were performed and action plans were used for following-up and implementation of corrective actions. Finally, microbiological and physicochemical parameters were analyzed and the obtained results were regarded as appropriate. Therefore, it is shown that HACCP constitutes an effective tool for identification of hazards, establishment of corrective actions and monitoring of the critical control points that impact the process and the quality of the final pharmaceutical product most significantly.

多目的最適化による遠心ポンプの低流量域における右上がり不安定特性の改善

Centrifugal pumps, which are widely used in industry for transporting liquids in plants and in water purification systems, and it is necessary to improve the instability characteristics at extremely low flow rate conditions. The negative slope of the characteristic curve is the evidence of instability of the flow, and it must be based on the local reverse flow zone and pre-whirl at impeller inlet. It is possible to predict the negative slope of the characteristics by unsteady numerical analysis at low flow rate, however, optimization design search requires many numerical analysis of individuals, it is not realistic solution to use the unsteady numerical analysis for the optimization.

A Water Purification System using Locally Sourced Materials and Removal of Total Petroleum Hydrocarbon in Contaminated Water

A Water Purification System using Locally Sourced Materials and Removal of Total Petroleum Hydrocarbon in Contaminated Water

EXPERIMENTAL STUDIES AND ANALYSIS ON THE TREATMENT OF GROUNDWATER USING SOLAR AND WIND ENERGY

Lack of safe water prevents 42 percent of the world's population from accessing sanitation. In 2021, the WHO estimated that there would be 784 million people without access to safe drinking water. With a well-planned system, the group aims to cut the number of people in need of drinkable water by half by 2015. These methods improve saltwater, which makes up 97 percent of the world's water. In this regard, a model that simulates the work of groundwater treatment firms using natural resources and renewable energy has been developed. There was a lack of continuous wind energy throughout most of Oman, where this model was put, and the necessity for a reverse osmosis system for constant maintenance because these projects rely on renewable energy everywhere. This article aims to create an autonomous desalination plant powered by solar and wind energy. A simulator model based on renewable energy groundwater purification systems was created for this aim. To treat subterranean water in distant areas of Oman using two renewable technologies to create enough electricity to run the reverse water purification and water purification system at the lowest cost. A turbine mounted vertically with a height of 1.5 meters and a diameter of 1 meter will produce 2304 liters per day and 800000 liters per year

All-Day Working Promoted Photovoltaic/Thermal Systems for Latent Heat Recycling and Water Purification

All-Day Working Promoted Photovoltaic/Thermal Systems for Latent Heat Recycling and Water Purification