Materials For Water Treatment Research Articles

Mechanochemical synthesis of microscale zero-valent iron/N-doped graphene-like biochar composite for degradation of tetracycline via molecular O2 activation

In this study, we prepared a micron zero-valent iron/N-doped graphene-like biochar (mZVI/NGB) composite using a mechanochemical method for tetracycline (TC) degradation through O2 activation. The mZVI and NGB components formed a strong coupling catalytic system, with mZVI acting as an electron pool and NGB as a catalyst for H2O2 generation. Under circumneutral pH (5.0–6.8), the mZVI/NGB composite exhibited exceptional TC removal efficiency, reaching nearly 100 % under optimal conditions. It also showed good tolerance to co-existing anions, such as Cl-, SO42-, and humic acid. Further studies found that the TC degradation mechanism was mainly ascribed to the non-radical pathway (1O2 and electron transfer), and the Fe2+/Fe3+ redox cycle on the composite's surface also played a crucial role in maintaining catalytic activity. This research contributes to the development of advanced materials for sustainable and effective water treatment, addressing pharmaceutical pollutant contamination in water sources.

Spicing up membrane distillation: Enhancing PVDF membrane performance with cinnamic acid

The increasing demand for freshwater is driving the rapid development of new water treatment materials. Furthermore, there is significant pressure to replace the toxic substances often used in membrane production with environmentally friendly, biocompatible, and natural compounds. In this work, poly(vinylidene fluoride) (PVDF) membranes were modified for the first time with a naturally occurring, non-toxic, biodegradable substance – cinnamic acid. The application of its molecules for membrane modification allows for diminishing the problem of bioaccumulation and toxicity in the environment. The procedure was selected with the accordance of green chemistry principles (green modifier – cinnamic acid, and green solvent – ethanol), and employed to chemically bind the modifier to the membrane surface. The modified membranes exhibited an increase in the hydrophobicity of the surface. The water contact angle increased from 124.7° for the pristine membrane to 139.3° for the membrane modified with a 10 % concentrated solution of cinnamic acid (PVDF-Cin10). All membranes possessed an excellent salt rejection coefficient. Membrane antiwetting features have been determined under challenging conditions of salt (3 M NaCl) and low surface tension liquid (sodium dodecyl sulfate). The dynamic goniometric studies were implemented to evolve membranes' wetting stability.

To treat wastewater with wastes: a highly efficient flocculant from fly ash and rice straw.

Water resources are vital for sustainable human life and economic activities. However, the issue of water pollution has reached alarming levels. Coking wastewater, known for its high concentrations of organic matter and toxic substances, poses significant environmental hazards. In response to this challenge, we developed a novel composite flocculant called polymeric aluminum ferric chloride (PAFC)/rice straw (PAFC/RS) from fly ash (a coal waste) and rice straw (an agricultural waste). The PAFC/RS was characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and Fourier transformed infrared (FT-IR). The flocculation performance of PAFC/RS was studied utilizing humic acid simulated coking wastewater as the target by measuring the chemical oxygen demand (COD), UV254, and turbidity. A removal efficiency of 97.3% for turbidity, 79.7% for COD, and 98.2% for UV254 was reached for the PAFC/RS with an optimal composition. It demonstrated a better flocculation effect compared to the traditional aluminum-iron-based inorganic flocculant. The PAFC/RS possesses great potential for a straightforward, cost-effective, and environmentally friendly water treatment material.

수처리용 섬유여과기 성능평가인자 도출 및 평가방법개발에 관한 연구

This study investigated the performance evaluation factors for the fiber filtration process in water treatment and researched the performance evaluation items and methods for assessing these factors. South Korea's water supply and sewage policies focus on modernizing civil structures and networks and introducing advanced treatment facilities. Reflecting these policies, the Waterworks Act describes the minimum requirements that water supply facilities must meet to ensure a consistent quality (water quality) of drinking water. Therefore, the Waterworks Act has introduced usage standards for water treatment processes and materials for water supply to manage the quality of drinking water. Firstly, the Ministry of Environment has issued water supply facility standards, which explain the minimum standards for water supply facilities. Secondly, there are hygiene and safety standards (suitability certification) and group standard certification. Standards and certifications are established to evaluate materials and products suitable for water supply facilities. Thus, two criteria are required to apply them to water supply facilities.
 In Republic of Korea, a new concept of water treatment process has been developed that can replace traditional water treatment processes. This involves a fiber filtration process that contracts and relaxes fiber strands, removing turbidity and suspended solids. There is a movement to adopt this process. Such fiber filters can provide better treatment efficiency, use smaller sites, and have faster processing speeds. However, the use of different evaluation methods by manufacturers has prevented consumers from accurately understanding the performance and raised doubts about the reliability of the technology.
 The result of this study is the development of a standardized performance evaluation method, and the derivation of performance evaluation factors for fiber filters. Through standardized performance evaluation factors and methods, an objective performance evaluation of the fiber filtration process can be conducted.

Bio-Based Aerogels for the Removal of Heavy Metal Ions and Oils from Water: Novel Solutions for Environmental Remediation.

Contamination of the aqueous environment caused by the presence of heavy metal ions and oils is a growing concern that must be addressed to reduce their detrimental impact on living organisms and safeguard the environment. Recent efficient and environmentally friendly remediation methods for the treatment of water are based on third-generation bioaerogels as emerging applications for the removal of heavy metal ions and oils from aqueous systems. The peculiarities of these materials are various, considering their high specific surface area and low density, together with a highly porous three-dimensional structure and tunable surface chemistry. This review illustrates the recent progress in aerogels developed from cellulose and chitosan as emerging materials in water treatment. The potential of aerogel-based adsorbents for wastewater treatment is reported in terms of adsorption efficacy and reusability. Despite various gaps affecting the manufacturing and production costs of aerogels that actually limit their successful implementation in the market, the research progress suggests that bio-based aerogels are ready to be used in water-treatment applications in the near future.

FLUORIDE IONS REMOVAL EFFICIENCY OF NATURAL/ACTIVATED ZEOLITE AND BENTONITE SORBENTS

Addressing the health concern of fluoride ions contamination in water, that cause such deceases as dental and skeletal fluorosis, requires the development of effective adsorption materials for water treatment. Our research objective was to evaluate the adsorption properties and capacities of zeolite and bentonite, sourced from Ukrainian deposits, and their acid-activated forms in relation to fluoride ions and estimate fitting this data to various adsorption models. Characterization of natural and acid-activated zeolite and bentonite sorbents was performed through X-ray diffraction to determine the phase composition of these substances. Adsorption experiments were carried out at different initial fluoride ions concentrations (3, 5, 10 and 15 mg/l) and pH (3.7; 7.5). Acidification (changing pH from 7.5 to 3.7) increase adsorption capacity of natural zeolite and bentonite more than twice. It was found that natural zeolite removes fluoride ions at the level of 67 % at pH 3.7 and a high dosage of sorbent – 10 g/l and an initial concentration of fluoride ions – 5 mg/l, while its acid‑activated form was more effective - the removal of fluoride ions is 86 % at a lower dosage of sorbent – 1 g/l. Similarly, natural bentonite demonstrated a maximum removal efficiency of 45 % at pH 3.7 and a dosage of sorbent – 10 g/l, and its acid-activated form allowed for the removal of fluoride ions of about 83 % at a dosage of sorbent – 2 g/l at the same fluoride ions concentration. It is shown that the Vagelar-Langmuir (VL) isotherm model is the most accurate for describing the process of fluoride ions adsorption by acid-activated forms of natural sorbents, where the R² values are close to 0.999, indicating monolayer adsorption on homogeneous active centers. The obtained results indicate the greater efficiency of acid-activated forms of natural sorbents and the prospects of their use for the removal of fluoride ions from water.

Recent Advances in Chitosan-based Nanocomposite Membrane Materials for Water Treatment

In recent years, research on chitosan (CS)-based nanocomposite membranes has made significant progress in the field of water treatment. This innovative membrane material incorporates a variety of excellent biological properties, including the biocompatibility and adsorption properties of the natural polymer chitosan (CS) and the introduction of nanotechnology. Furthermore, it enables the composite material to have excellent functional characteristics, such as higher water flux and selectivity. Furthermore, the enhancement of the structural and intrinsic properties of membrane materials will facilitate the attainment of further advancements in a multitude of performance characteristics, including stability, durability, and adsorption selectivity. Consequently, this field has become a promising area of research in water treatment technology, attracting extensive research and attention. However, the publication of a large number of related research reports in recent years, accompanied by numerous and complex performance optimization schemes and research ideas, has resulted in a paucity of articles that summarize these performance optimization strategies and research paths. Consequently, there are few meaningful references for subsequent research. In light of the aforementioned considerations, this paper will provide a comprehensive review of the most recent research advances in the field of water treatment, with a particular focus on the latest research strategies and frameworks for optimizing the performance of related materials. Furthermore, this paper will illustrate the innovative and beneficial applications of such materials from various vantage points, including their sources and preparation processes. It is anticipated that this paper will serve as a valuable source of inspiration for further research in this field.

Structure Evolution of Iron (Hydr)oxides under Nanoconfinement and Its Implication for Water Treatment.

In the development of nanoenabled technologies for large-scale water treatment, immobilizing nanosized functional materials into the confined space of suitable substrates is one of the most effective strategies. However, the intrinsic effects of nanoconfinement on the decontamination performance of nanomaterials, particularly in terms of structural modulation, are rarely unveiled. Herein, we investigate the structure evolution and decontamination performance of iron (hydr)oxide nanoparticles, a widely used material for water treatment, when confined in track-etched (TE) membranes with channel sizes varying from 200 to 20 nm. Nanoconfinement drives phase transformation from ferrihydrite to goethite, rather than to hematite occurring in bulk systems, and the increase in the nanoconfinement degree from 200 to 20 nm leads to a significant drop in the fraction of the goethite phase within the aged products (from 41% to 0%). The nanoconfinement configuration is believed to greatly slow down the phase transformation kinetics, thereby preserving the specific adsorption of ferrihydrite toward As(V) even after 20-day aging at 343 K. This study unravels the structure evolution of confined iron hydroxide nanoparticles and provides new insights into the temporospatial effects of nanoconfinement on improving the water decontamination performance.

Vertical porous aerogel based on polypyrrole and bimetallic modified β-cyclodextrin polymer-chitosan for efficient solar evaporation

Solar-driven interfacial evaporation (SDIE) stands out as a prospective technology for freshwater production, playing a significant role in mitigating global water scarcity. Herein, a cyclodextrin polymer/chitosan composite aerogel (PPy-La/Al@CDP-CS) with vertically aligned channels was prepared as a solar evaporator for efficient solar steam generation. The vertically aligned pore structure, achieved through directional freezing assisted by liquid nitrogen, not only improves water transport during evaporation but also enhances light absorption through multiple reflections of sunlight within the pores. The polypyrrole particles sprayed on the surface of the aerogel acted as a light-absorbing layer, resulting in an impressive absorbance of 98.15 % under wetting conditions. The aerogel has an evaporation rate of 1.85 kg m−2 h−1 under 1 kW m−2 irradiation. Notably, the vertical pore structure of the aerogel allows it to exhibit excellent evaporation performance and salt resistance even in highly concentrated salt solutions. Furthermore, this aerogel is an excellent solar-driven interfacial evaporator for purifying seawater and fluoride-containing wastewater. This photothermal aerogel has the advantages of excellent performance, low cost, and environmental friendliness, and thus this work provides a new approach to the design and fabrication of solar photothermal materials for water treatment.

Bio-Inspired Functional Materials for Environmental Applications.

With the global population expected to reach 9.7 billion by 2050, there is an urgent need for advanced materials that can address existing and developing environmental issues. Many current synthesis processes are environmentally unfriendly and often lack control over size, shape, and phase of resulting materials. Based on knowledge from biological synthesis and assembly processes, as well as their resulting functions (e.g., photosynthesis, self-healing, anti-fouling, etc.), researchers are now beginning to leverage these biological blueprints to advance bio-inspired pathways for functional materials for water treatment, air purification and sensing. The result has been the development of novel materials that demonstrate enhanced performance and address sustainability. Here, an overview of the progress and potential of bio-inspired methods toward functional materials for environmental applications is provided. The challenges and opportunities for this rapidly expanding field and aim to provide a valuable resource for researchers and engineers interested in developing sustainable and efficient processes and technologies is discussed.

Adsorption of Ca (II), Mn (II), Fe (III), Mg (II), and Pb (II) Ions from New Valley Groundwater Using Illite and Nanoparticles

Heavy metal pollution is a significant environmental concern due to its potential hazards. In this study, the adsorption of Ca (II), Mn (II), Fe (III), Mg (II), and Pb (II) ions from diluted aqueous solutions was investigated using both illite and nano-illite particles. The integration of illite as a natural and cost-effective material in water treatment for areas facing water pollution challenges offers a holistic solution with positive implications for the environment, economy, and public health. The multifaceted benefits of illite underscore its potential as a valuable tool in addressing water-related issues in remote and economically constrained regions. The synthesis and characterization of nano-illite were conducted through SEM, TEM, and FTIR spectroscopy. Notably, the TEM analysis revealed that the particle size of nano-illite (ranging from 2 to 4 nm) was smaller than that of illite (ranging from 20 to 30 nm). For the adsorption experiments, batch tests were performed, and the optimal conditions were determined. It was found that the highest adsorption efficiency for the studied metal ions was achieved at a pH of 7, a contact time of 60 minutes, an illite dosage of 0.4 g, and a nano-illite dosage of 0.3 g. Furthermore, the adsorption kinetics were analyzed using the pseudo-second-order kinetic model, while the adsorption isotherms were evaluated using the Langmuir model. This investigation provides valuable insights into the effective removal of heavy metal ions from aqueous solutions using illite and nano-illite particles. The results highlight the potential applicability of these adsorbents in addressing heavy metal pollution, thereby contributing to the mitigation of environmental risks associated with such contaminants.

Gamma irradiation-assisted synthesis of ultrafine AgNPs incorporated in MIL-100(Fe) for efficient catalytic reduction of dye

In this study, we report on the synthesis and characterization of ultrafine silver nanoparticles (AgNPs) incorporated in MIL-100(Fe) metal-organic frameworks (Ag@MIL-100(Fe)) for the efficient catalytic reduction of dyes in water treatment applications. The Ag@MIL-100(Fe)were synthesized using a one-step and effective technique and characterized using various techniques, including X-ray diffraction, transmission electron microscopy, and ultraviolet visible spectroscopy. The results showed that the AgNPs were highly stable and had an average size of ∼3 nm, with excellent distribution within the MIL-100(Fe) framework. The catalytic performance of the hybrid materials was evaluated using the reduction of methyl orange dye as a model reaction, and the results showed that the Ag@MIL-100(Fe) had a high catalytic activity. The enhanced catalytic activity of the nanoparticles is attributed to the synergistic effect between the AgNPs and the MIL-100(Fe) framework, which provides a highly stable and porous matrix for the efficient reduction of dyes. The results of this study demonstrate the potential of Ag@MIL-100(Fe) as a promising material for water treatment and environmental remediation applications.

Hybrid Photoelectrocatalytic TiO2-Co3O4/Co(OH)2 Materials Prepared from Bio-Based Surfactants for Water Splitting.

The development of new photoanode materials for hydrogen production and water treatment is in full progress. In this context, hybrid TiO2-Co3O4/Co(OH)2 photoanodes prepared using the sol-gel method using biosurfactants are currently being developed by our group. The combination of TiO2 with a cobalt-based compound significantly enhances the visible absorption and electrochemical performance of thin films, which is mainly due to an increase in the specific surface area and a decrease in the charge transfer resistance on the surface of the thin films. The formation of these composites allows for a 30-fold increase in the current density when compared to cobalt-free materials, with the best TiO2-CoN0.5 sample achieving a current of 1.570 mA.cm-2 and a theoretical H2 production rate of 0.3 µmol.min-1.cm-2 under xenon illumination.

Heteroatom-modulated NiCo2O4 apparent energy activation of PMS for tetracycline removal: Mechanism and toxicity analysis

Heteroatom doping to reconfigure the electronic structure of heterogeneous catalysts is expected to lead to the development of advanced oxidation water purification materials with superior performance and greater stability. Herein, a series of catalysts with different elemental doping was developed by a simple and environmentally friendly one-step self-propagating combustion method to remove Tetracycline (TC). After S-doping, the normalized kinetic constant of TC was significantly increased from 30.49 to 159.41 min−1M−1 within 30 min, which is even higher than most recent heterogeneous catalysts. The prepared S-doped NiCo2O4 (NCO–S) exhibits an extremely promising catalytic performance for oxidation (92.8 %) and mineralization (65.9 %) of TC in a wide pH range (3–11). The resistance to interference is excellent for inorganic ions and even in real water samples. Quenching experiments, electron paramagnetic resonance (EPR), and electrochemical analyses demonstrated that the non-radical oxidation pathway, including electron transfer and 1O2, dominated the degradation process after S doping. It is speculated that possible intermediates and toxicological studies are discussed, finding that the overall degradation process is moving towards low toxicity to reveal prospects for large-scale applications. This work not only provides a way to remove TC, but may also inspire the design of more efficient and stable materials for water treatment and other applications.

Graphene Oxide: A Key Solution for Future: Recent Achievements as A New Adsorbent for Water Treatment Applications: Review

Polluted water has been considered a critical issue nowadays, threatening the environment and lives of living creatures. Because of technological and industrial advancements, as well as increased social activities of humans in various countries, pollution sources have multiplied. To reduce the impact of this problem, many techniques have been developed in order to reach zero discharge pollution. In the last decade, graphene oxide (GO) - a member of the graphene nanomaterials family, has been the focus of many research efforts in the water treatment sector because of its extraordinary properties. This review highlights the research efforts conducted to investigate GO as a novel adsorbent for water treatment applications and recent fulfilments in the last 3 years. The synthesis techniques, properties, and efficiency of this material in water treatment will be explained. All results confirm the future role of GO as an efficient absorbent to solve wastewater purification challenges, but the big challenge is to reduce time and simplify the complicated extent of synthesis stages, besides reducing the high cost of production methods. According to the review, Iraqi researchers' efforts to use this nanomaterial in water purification are still in their early stages.

Synthesis of hybrid layered double hydroxides (HLDH) and application as adsorbent for removal of direct sky-blue dye

Hybrid Layered Double Hydroxides (HLDH) are promising adsorption materials for water treatment due to their excellent anion exchange capacities, abundance of active sites, and eco-friendliness. HLDH was synthesized utilizing the co-precipitation technique in this work to demonstrate its applicability for the removal of direct sky-blue dye via an adsorption procedure. The effects of pH, dose, contact time, initial dye concentration, and temperature on the direct sky-blue dye adsorption efficiency were thoroughly investigated. The adsorbents were analyzed using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), energy dispersive X-ray (EDX), and Brunauer–Emmett–Teller (BET). Under the best conditions, the maximum adsorption capacity has been achieved for Mg–Cr–Cl (42.95 mg/g) > Zn–Al–CO3 (39.76 mg/g) > Mg–Fe–Cl (38.08 mg/g). The adsorption of dyes on Mg–Cr–Cl, Zn–Al–CO3, and Mg–Fe–Cl followed a pseudo-second-order kinetic model and exhibited Langmuir-type monolayer adsorption. The influence of temperature was studied to determine the thermodynamic parameters. The estimated results showed spontaneous and exothermic adsorption processes. Electrolyte enhances the adsorption capacity to some extent, while surfactants block the sites, thus reducing the adsorption capacity. The maximum desorption of dye was influenced by the sodium hydroxide solution. The research described here might be utilized to create novel adsorbents with improved adsorption capacities for preserving the aquatic environment.

Parameters Synthesis of Na-Magadiite Materials for Water Treatment and Removal of Basic Blue-41: Properties and Single-Batch Design Adsorber

Na-magadiite materials were prepared from a gel containing a silica source, sodium hydroxide, and water via hydrothermal treatment at different temperatures (130 °C to 170 °C) and periods of time (1 day to 10 days). In this study, four silica sources were selected (fumed silica, colloidal silica, Ludox HS-40%, and Ludox AS-40%). Variable conditions such as sodium hydroxide and water contents were explored at a specific temperature and reaction time. The obtained materials were characterized by using X-ray diffraction (XRD), thermogravimetry differential thermal analysis TG-DTA, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), Fourier Transform Infrared spectroscopy (FTIR), solid 29Si magic angle spinning magnetic nuclear resonance (MAS MNR, and nitrogen adsorption isotherms. A pure Na-magadiite phase was obtained from the four silica sources at a synthesis temperature of 150 °C after a period of one to two days with a characteristic basal spacing of 1.54 nm. At a longer reaction time of 3 days and a higher temperature of 170 °C, Na-kenyaite with a basal spacing of 2.01 nm was achieved, in addition to a quartz phase. The content of water or sodium hydroxide in the gel affected the nature of the prepared phases. A cauliflower-like morphology was obtained from colloidal silica sources, while a different morphology was achieved using solid fumed silica. The 29Si solid NMR confirmed the presence of Q3 and Q4 silicon sites in the Na-magadiite materials. The optimal Na-magadiite materials at 150 °C for 2 days were assessed for their ability to remove Basic Blue-41 dye from artificially contaminated aqueous solution. The Langmuir equation was used to estimate the maximum removal capacity. A maximum removal capacity of 219 mg/g was achieved using Na-magadiite prepared from a Ludox-HS40% silica source, and a maximum removal capacity of 167 mg/g was observed for Na-magadiite prepared from fumed silica. Basic Blue-4’s removal percentage was enhanced at basic pH levels (8 to 10) to a maximum of 95%. These materials could be regenerated for seven cycles of reuse with a reduction of 27 to 40% of the original values. Therefore, Na-magadiite materials are promising and efficient removal agents for the removal of Basic Blue-41 from effluents.

UiO-66 octahedrons for adsorptive removal of direct blue-6: process optimization, interaction mechanism, and phytotoxicity assessment.

The materials for water treatment have been evolving in multitude of dimensions, indicating the importance of water reuse and increasing level of water pollution around the globe. Among the various materials that are utilized in wastewater treatment, the material that has attracted the research community for the past decades is the metal organic framework (MOF). In this work one of the water stable and microporous MOF, UiO-66, and its aminated version has been employed to adsorb an anionic azo dye, direct blue-6 (DB-6), from the aqueous matrix. Performance of both the MOFs was compared to know the efficiency under varying solution conditions. The optimized parameters for DB-6 adsorption by UiO-66 was performed using response surface methodology. This numerical optimization was further extended with canonical and ridge analysis. Under optimal conditions, the materials were exhibiting a good adsorption capacity of 754.4mg/g. The materials were analyzed in terms of morphology, crystallinity, thermal stability, and surface area using instruments like X-ray diffraction, electron microscopy, thermogravimetric analysis, and BET surface area analysis. The mechanism of interaction between UiO-66 and DB-6 molecule was elucidated with the help of XPS analysis which helps to know the main interacting group of UiO-66. This study was concluded with a phytotoxicity analysis of DB-6 and the antioxidant system of Vigna radiata assessed using pre and post adsorbed water.

Engineering In Situ Catalytic Cleaning Membrane Via Prebiotic-Chemistry-Inspired Mineralization.

Pressure-driven membrane separation promises a sustainable energy-water nexus but is hindered by ubiquitous fouling. Natural systems evolved from prebiotic chemistry offer a glimpse of creative solutions. Herein, a prebiotic-chemistry-inspired aminomalononitrile (AMN)/Mn2+ -mediated mineralization method is reported for universally engineering a superhydrophilic hierarchical MnO2 nanocoating to endow hydrophobic polymeric membranes with exceptional catalytic cleaning ability. Green hydrogen peroxide catalytically triggered in-situ cleaning of the mineralized membrane and enabled operando flux recovery to reach 99.8%. The mineralized membrane exhibited a 9-fold higher recovery compared to the unmineralized membrane, which is attributed to active catalytic antifouling coupled with passive hydration antifouling. Electron density differences derived from the precursor interaction during mediated mineralization unveiled an electron-rich bell-like structure with an inner electron-deficient Mn core. This work paves the way to construct multifunctional engineered materials for energy-efficient water treatment as well as for diverse promising applications in catalysis, solar steam generation, biomedicine, and beyond.

Special Issue on “Advanced Catalytic Material for Water Treatment”

Water is the source of life on Earth [...]