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Amidst worsening water scarcity in the urban region, exploring alternative water sources is crucial. Atmospheric water extraction (AWE) technology emerges as a cost-effective and efficient remedy for the escalating issue of water scarcity. The objective of this research is to experimentally explore a novel AWE system that incorporates phase change material (PCM). This system is designed to facilitate uninterrupted water generation, even when there is no solar energy. It comprises of a solar air heater based on both-sides open evacuated tube collector having an area of 4.86 m2, which is encapsulated with acetamide-PCM. Additionally, it incorporates a silica gel filled desiccant bed and an air-cooled heat exchanger for vapor condensation. The system is investigated for two different desiccant bed weights of 15 kg (case 1) and 20 kg (case 2), respectively. The system's effectiveness is examined based on rate of adsorption, rate of regeneration, thermal, overall & exergy efficiency. The economic, environmental & enviro-economic analysis is also presented to ensure the system's sustainability & feasibility for its practical use. The results demonstrate that for case 2 the system extracts 4.1 L/day (0.843 L/m2/day) fresh water with 12.65%, 10.48% and 5.65% thermal, overall and exergy efficiency, respectively, for 20 kg desiccant bed weight. The fresh water cost is 0.12 $/L with 2 years & 1 month of payback time and 4 years & 7 months of energy payback period. The environmental & enviro-economic analysis ensures the system's eco-friendliness. Additionally, rigorous quality testing of the extracted water is carried out to affirm its suitability for safe consumption. • PCM encapsulated solar air heater for atmospheric water extraction. • Both sides open evacuated tube collector produces hot air of 130.10 °C. • Maximum water extracted is 4.1 L/day using air-cooled heat exchanger. • Thermal & exergy efficiency reported is 12.65 % & 5.65 %, respectively. • Water generation cost is 0.12 $/L, with system payback time of 2 years & 1 month. [ABSTRACT FROM AUTHOR]

Herein, we report the designing of a C3N4/BiOI heterostructure that is supported on gum acacia-crosslinked-poly(acrylamide) hydrogel to fabricate a novel nanocomposite hydrogel. The potential application of the obtained nanocomposite hydrogel to remediate crystal violet dye (CVD) in an aqueous solution was explored. The structural and functional analysis of the nanocomposite hydrogel was performed by FTIR (Fourier transform infrared spectroscopy), X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The different reaction parameters, such as CVD concentration, nanocomposite hydrogel dosage, and working pH, were optimized. The C3N4/BiOI heterostructure of the nanocomposite hydrogel depicts Z-scheme as the potential photocatalytic mechanism for the photodegradation of CVD. The degradation of CVD was also specified in terms of COD and HR-MS analysis was carried to demonstrate the major degradation pathways. [ABSTRACT FROM AUTHOR]

• Atmospheric air to water generation using both end open evacuated tube collector. • Hot air temperature available from 5.07 m2 solar collector area is 140.9 °C. • 3.080 L/day of fresh water is produced by using an air-to-air condenser. • The system energy & exergy efficiency is 9.65% & 3.69%, respectively. • The cost of fresh water generation is 0.12 $/L, which is affordable. Regional economic, social, and ecological security are all entwined and influenced by the availability of water. Since the available water resources are depleting at a very faster rate and people are restricted to access the clean water, it is urgent to discover new & alternative sources of fresh water to meet everyone's requirements. An inexpensive and effective solution to the rising problem of the water shortage can be atmospheric air to water generation (AWG) technology. This study involves the development and experimental investigation of a novel AWG system based on adsorption under ambient conditions. Both end open evacuated tube collector solar air heater (ETC-SAH) with 5.07 m2 solar collector area and an air-to-air condenser is used. The system's performance is evaluated based on several key parameters, including adsorption & regeneration rate, energy & exergy efficiency, and economic analysis. The fresh water yield reported from the system is 3.08 L/day at 0.12 $/L cost. The energy & exergy efficiency reported by the system is 9.65% & 3.69%, respectively. Additionally, the water produced is subjected to testing at a regionally certified laboratory to confirm its safety for consumption. [ABSTRACT FROM AUTHOR]

The lack of fresh water, especially for the land-locked & arid regions, is becoming a significant barrier to the sustainable development of humanity. This has generated an urgent need to explore the solar-driven atmospheric water generation (S-AWG) technologies with high water yield. This research experimentally compares the performance of silica gel and molecular sieve on a novel S-AWG system. 25 kg of each desiccant material is used in a packed desiccant bed structure. In the nocturnal phase, adsorption is performed followed by regeneration during the day using hot air generated from evacuated tube solar air heater (ET-SAH). An air-to-air heat exchanger is employed for condensing the water vapors released in the process air after the desiccant bed regeneration. The water generated from silica gel is 1790 ml with energy & exergy efficiency of 23.14% & 10.43%, respectively. From the molecular sieve, 350 ml of water is generated with energy & exergy efficiency of 21.74% & 9.58%, respectively. The economic analysis of the system reveals that the cost of water generated from silica gel is 0.21 $/L, while from molecular sieve is 1.21 $/L. Water testing reports of the produced water using both the desiccant materials infers that it is drinkable. [Display omitted] • Solar atmospheric water generation (S-AWG) based on air-to-air heat exchanger. • Comparison of S-AWG system by using silica gel & molecular sieve. • 1790 ml/day water is produced from silica gel & 350 ml/day from molecular sieve. • Energy & exergy efficiency of the S-AWG system is 23.14% & 10.43%, respectively. • Water generated from silica gel costs 0.21 $/L. [ABSTRACT FROM AUTHOR]

The pulp and paper industry consumes a huge amount of water and releases more polluted and colored wastewater every year. Many conventional techniques are used in the treatment of paper industry wastewater. However, for color removal from paper mill effluent, there is no proven method so far, on an industrial scale. Due to high energy input and high cost, there is an urgent need to find out a new technique that must be sustainable, economical, and environment friendly. Various methods have been investigated on bench scale and pilot scale also but no proven method for color removal on an industrial scale. The paper provides an overview of the color removal techniques from different sources of pulp and paper mill wastewater discharged by various industries. The review described various components involved in various processes for color removal from paper mill waste water. The present works focus on processes like chemical, chemical/physical, biological, physicochemical, and electrochemical applied in color removal from paper mill wastewater. The present review gives key information on the effectiveness, use, betterment, and limitations of numerous methods of treatment targeted at color removal from paper mill wastewater using various techniques still under evolution. • A critical study made on color removal from paper mill effluent using various methods. • Examined color removal efficiencies using conventional and advanced techniques. • Study on Cost analysis in color removal from paper mill effluent. • Future research suggestions described for better implementation of the processes. [ABSTRACT FROM AUTHOR]

Microplastics (MPs), as emerging pollutants, have attracted the attention of environmentalists, statespersons, and the scientific community over the last few decades. To address the spread of MPs in the environment, it is imperative to develop various removal techniques and materials that are effective, scalable, and ecologically benign. However, to the best of our knowledge, no review has systematically examined the removal of MPs using adsorption or provided an in-depth discussion on various adsorbents. Adsorption is an inexpensive and effective technology for wastewater treatment. Recently, many researchers have conducted studies on MP remediation using diverse adsorbent materials, such as biochar, activated carbon, sponges, carbon nanotubes, metal-layered oxides, metal-organic frameworks (MOFs), and zeolites. Each adsorbent has advantages and disadvantages. To overcome their disadvantages, researchers have been designing and developing hybrid adsorbents for MP remediation. This review provides insights into these individual adsorbents and also discusses hybrid adsorbents for MP removal. Finally, the review elaborates on future possibilities and ways to enable more efficient, scalable, and environmentally friendly MP cleanup. Overall, this review bridges the gap between contemporary MP remediation using adsorption techniques and adsorbent development. [Display omitted] • Adsorption-based microplastic remediation was reviewed. • The factors affecting microplastic adsorption were thoroughly discussed. • A comprehensive analysis is presented on several microplastic adsorbents. • Microplastic adsorption challenges and future perspectives are examined. [ABSTRACT FROM AUTHOR]

We report the fabrication of a novel waste-derived biochar-impregnated Bi 5 O 7 Br/Fe 3 O 4 (WBF) magnetic composite for photocatalytic removal of malachite green pollutant. The newly prepared catalyst was applied for the removal of malachite green dye under visible light irradiation. It was found that the composite degrades 99.39% MG dye within 20 min of the experiment as compared to Bi 5 O 7 Br, Fe 3 O 4, and biochar with 83.19%, 75.09%, and 55.47% in the 50-min experiment. The findings demonstrated that a photocatalytic integrated composite quickly transfers charges across surfaces and effectively separates electron-hole pairs, considerably increasing charge carrier separation and photocatalytic activity. Further, the kinetics show that the rate constant for WBF composite is 7.1 times higher than that observed for Bi 5 O 7 Br. Scavenging experiments reveal the huge role of.OH and •O 2 − radicals in malachite green degradation. Additionally, the magnetic nature of the catalyst ensures the easy separation of the catalyst during photocatlytic experiments and reduces the chance of secondary pollution. The results showed that integrating Bi 5 O 7 Br and biochar with Fe 3 O 4 to create photocatalytic composites is a very efficient strategy to boost photocatalytic activity for environmental waste water treatment. [Display omitted] • Newly designed waste derived bio-char impregnated Bi 5 O 7 Br/Fe 3 O 4 magnetic composite was successfully synthesised. • Composite degrades 99.39% MG dye within 20 min of the experiment. • Rate constant for MG removal for WBF composite is 7.1 times higher than that observed for Bi 5 O 7 Br. • Integrated composite improves the charge carrier separation and photocatalytic activity. • Composite exhibit sound stability upto six degradation cycles. [ABSTRACT FROM AUTHOR]

Rapid industrial development is associated with high discharge of toxic pollutants into the environment. The industries discharge their wastewater containing organic pollutants directly into the water system without treating them that has posed many serious threats to environmental protection. The use of bioadsorbents for the removal of such toxic pollutants from the waste water due to its simple synthesis, easy operation, effectiveness, and economic viability have emerged a new dimension in the wastewater treatment approaches. Various adsorbents have been prepared to examine their adsorption capacity against different adsorbates, but, to attain sustainability, biocompatibility, and biodegradation, bio-adsorbents have been found to won the battle. Seaweed derived polysaccharide; Carrageenan (CR) has been proven to be an excellent adsorbent for the wastewater treatment. It has been successfully modified with various components to form CR based-magnetic composites, hydrogels, nanoparticle modified CR composites and many others to enrich and diversify its properties. In this review, we have explained the adsorption behaviour of various carrageenan based adsorbents for the removal of different dyes. The influence of various parameters such as the effect of initial concentration, adsorbent dosage, contact time, pH, temperature, and ion concentration on dye adsorption is well explained. This paper also summarizes the structure, morphology, swelling ability, and thermal stability of carrageenan. The data also expounds on the adsorption capacity, kinetic model, isotherm model, and nature of the adsorption process. Different types of solvents are used for the regeneration and reusability of carrageenan adsorbents and their regeneration studies and desorption efficiency is well-explained. The adsorption mechanism of dyes onto carrageenan based adsorbents has been well described in this review. This review provides a deep insight about the use of carrageenan based adsorbents for the wastewater treatment. [Display omitted] • A comprehensive review based on carrageenan or its various composites. • Carrageenan based adsorbents for removal of numerous pollutants were surveyed. • Various influential factors on the adsorption was taken into consideration. • Various categories of carrageenan were studied. [ABSTRACT FROM AUTHOR]

Polysaccharide-based hydrogels offer a great overlook for environmental applications and help in the elimination of various noxious pollutants from the water system. Novel carrageenan and itaconic acid-based superadsorbent hydrogel having appreciable swelling properties and adsorption capacity towards Methylene blue (MB), Crystal violet (CV), and Methyl Red (MR) was synthesized by suspension polymerization technique. The swelling study showed the dependency upon the temperature in which the swelling rate increased with increasing temperature with a maximum swelling rate of 417% at 318 K. For ascertaining the maximum adsorption capacity, various influential parameters such as contact time, adsorbent dose, dye concentration, and temperature were systematically studied. Maximum adsorption capacity as calculated from the Langmuir isotherm was 2439.02, 1111.11, and 666.68 mg/g for MB, CV, and MR, respectively. Thermodynamic studies revealed the spontaneous nature of the undertaken dye adsorption experiment. Overall, the present study reveals that the synthesized superadsorbent hydrogel can be used as an efficient adsorbent for the removal of dyes from an aqueous solution. [Display omitted] • Superadsorbent hydrogel designed for the adsorptive removal of cationic dyes. • Maximum adsorption capacity obtained for MB followed by CV and MR. • Results have been analyzed by isotherm and kinetic studies. • Superadsorbent hydrogel successfully recycled for consecutive 5 cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] • porous Zn/Fe LDH exhibited appreciable adsorption capacity. • Successful decomposition of H 2 O 2 present between the LDH layers. • Introduction of pores in the layers enhanced the surface area and adsorption activity. • Successfully reusable for consecutive 6 cycles adsorption cycles. Present work include the designing of a novel porous Zn/Fe layered double hydroxide (LDH) based adsorbent using a combination of three methods, namely, co-precipitation, hydrothermal, and thermal treatment. The Zn/Fe LDH was synthesized by co-precipitation followed by hydrothermal method. The LDH was then intercalated with H 2 O 2 and its decomposition under the thermal treatment created oxygen bubbles that pierce holes in the layered structure of the LDH by local pressure build-up. Major techniques used for assessing the morphology and surface area characteristics of the LDH and porous LDH were Scanning electron microscope (SEM) and Brunauer-Emmet-Teller (BET). The intercalation of H 2 O 2 and its later decomposition triggered by thermal treatment lead to the introduction of pores in the LDH layers that increased the surface area from 108.863 m2/g to 168.923 m2/g. The synthesized adsorbent was utilized for the removal of an antibiotic; ciprofloxacin (CIP) from the aqueous solution. The porous Zn/Fe LDH adsorbent was featured with an admirable CIP adsorption capacity of 344.83 mg/g at pH 6.5 and temperature 298 K. The adsorption of CIP onto porous Zn/Fe LDH adsorbent followed the Freundlich isotherm model and pseudo-second-order kinetic model. The temperature increase negatively affected the adsorption rate. The adsorption mechanism of CIP onto porous Zn/Fe LDH was also projected and established, and Cπ- metal interactions, hydrogen bonding, and electrostatic interactions, were found to be the major interactive forces. The thermodynamic study revealed the exothermic and spontaneous nature of the adsorption experiments. Overall, the synthesized adsorbent is sustainable in terms of its usability and non-toxic nature. [ABSTRACT FROM AUTHOR]