Sustainable urea treatment by environmental-friendly and highly hydrophilic vesicle-like iron phosphate-based carbon.

Despite the versatile potential applications of urea, its unfavorable characteristics for conventional treatment methods hinder its utilization. Therefore, this study developed vesicle-like iron phosphate-based carbon (IP@C400) as a breakthrough urea removal and recovery material for a wide range of urea-containing sources. IP@C400 rapidly exhibited an exceptional capacity (2242 mg/g in 1 h) across a wide range of pH, even in synthetic hemodialysis wastewater with high urea concentrations and diverse co-existing components, compared with the 60 prominent adsorbents. The adsorption process followed dual Pseudo-kinetic, Langmuir-isotherm models with the involvement of primary robust physical (i.e., H-bonding and electrostatic interaction) and chemical mechanisms (i.e., hydrolysis). Remarkably, IP@C400 can maintain high urea removal (90 %) or recovery efficiency (95 %) even after 10 cycles with minimal leakages of Fe and P (far below WHO and EUWFD standards)-a significant improvement over disposable options. IP@C400 could also perform efficiently on batch and a new approach integrating with a naturally accessible material based on the fixed-bed column using low-range urea realistic samples, achieving 65.2 L water over 10 cycles with undetected urea, neutral pH, and well-aligned water safety standards with a minimal adsorbent dose (0.1 g.L-1) and economical cost ($0.05 L-1). Lastly, its environmentally friendly nature, which contains essential nutrients for plant growth, further enhances its recyclability after release. Thus, IP@C400 offers a solution to environmental sustainability and the urgent ultrapure water issue that industries are facing.

Ultrahigh-purity ammonia recovery from synthetic coke wastewater via membrane contactor: Overcoming phenolic interference and assessing cost efficiency.

Ammonia recovery from industrial wastewater using membrane contactor processes is emerging as a promising method owing to the diverse applications of ammonia. This study uniquely addressed ammonia recovery from coke plant wastewater, which is challenging due to the presence of numerous toxic and volatile phenolic compounds. Experiments were conducted using a synthetic coke plant effluent to assess the effects of various pH levels and temperatures on ammonia recovery. Specifically, the aim was to achieve high-purity ammonia recovery while minimizing the permeation of phenolic compounds. The results demonstrate that ammonia recovery in the membrane contactor processes is highly efficient, even in the presence of phenolic compounds. During temperature variations at 25 °C and 40 °C, the recovery of ammonia increased from 42.36% to 52.97% at pH 11. Additionally, increasing the pH of a feed solution from 7 to 12 significantly increased the ammonia content to 58.3%. At this pH, the recovered ammonia was of exceptional purity (>99%), with phenol, p-Cresol, and 2,4-xylenol present at negligible concentrations (0.001%, 0.002%, and 0.004%, respectively). This was attributed to the ionization of phenolic compounds at higher pH levels, which prevents their permeation through the hydrophobic membrane. The estimated cost analysis revealed that the membrane contactor process at pH 12 was approximately 1.41 times more cost-effective than conventional air-stripping processes over eight years of operating period (pH-12 membrane contactor: $19.79; pH-12 air stripping: $23.75). This study provides a detailed analysis of the optimal conditions for selective ammonia recovery from complex wastewater, highlighting both effective treatment and sustainable resource recovery and offering a superior alternative to traditional methods.

Interconnection between renewable energy technologies and water treatment processes.

The renewable-energy-based water-energy nexus is a promising approach that contributes to climate change mitigation. Increasing concerns on GHG emission and energy demand, policies have been implemented in many countries to make use of renewable energy as much as possible. Renewable energy technologies can be directly employed in desalination processes, including membrane-based (e.g., reverse osmosis (RO) and membrane distillation (MD)) and thermal-based (e.g., multistage flash distillation (MSF) and multieffect distillation (MED)) technologies. Although the production capacities of fossil-based desalination processes (RO, MD, and MED) are higher than those of renewable-energy-based desalination processes, most latter desalination processes have lower specific energy consumption than conventional processes, which may offer potential for the implementation of renewable energy sources. In addition to the direct application of renewable energy technology to desalination, biofuels can be produced by converting algal lipids obtained from the growth of algae, which are associated with wastewater bioremediation and nitrogen and phosphorus removal during wastewater treatment. Salinity gradient power can be harvested from brine originating from desalination plants and freshwater driven by pressure-retarded osmosis or reverse electrodialysis. This study provides an overview of these approaches and discusses their effectiveness. It not only offers insights into the potential of applying renewable energy technologies to various water treatment processes but also suggests future directions for scientists to further enhance the efficiency of renewable energy production processes for possible implementation.

Real-time diagnosis and monitoring of biofilm and corrosion layer formation on different water pipe materials using non-invasive imaging methods.

Water distribution networks play a crucial role in ensuring a reliable water supply, yet they encounter challenges such as corrosion, scale formation, and biofilm growth due to interactions with environmental elements. Biofilms and corrosion layers are significant contaminants in water pipes, formed by complex interactions with pipe materials. As the structure of these contamination layers varies depending on the pipe material, it is essential to investigate the contamination layer for each material individually. Specifically, biofilm growth is typically investigated concerning organic sources, while the growth of humus layers is examined in relation to inorganic elements such as manganese (Mn), iron (Fe), and aluminum (Al), which are major elements and organic substances found in water pipes. Real-time imaging of recently contaminated layers can provide important insights to improve system performance by optimizing operations and cleaning processes. In this study, cast iron (7.10 ± 0.78 nm) exhibits greater surface roughness compared to PVC (5.60 ± 0.14 nm) and provides favorable conditions for biofilm formation due to its positive charge. Over a period of 425 h, the fouling layer on cast iron and PVC surfaces gradually increased in fouling thickness, porosity, roughness, and density, reaching maximum value of 29.72 ± 3.6 µm, 11.44 ± 1.1%, 41673 ± 1025.6 pixels, and 0.80 ± 0.3 fouling layer pixel/layer pixel for cast iron, and 8.15 ± 0.4 µm, 20.64 ± 0.9%, 35916.6 ± 755.7 pixels, and 0.58 ± 0.1 fouling layer pixel/layer pixel, respectively. Within the scope of the current research, CNN model demonstrates high correlation coefficients (0.98 and 0.91) in predicting biofilm thickness for cast iron and PVC. The model also presented high accuracy in predicting porosity for both materials (over 0.91 for cast iron and 0.96 for PVC). While the model accurately predicted biofilm roughness and density for cast iron (correlation coefficients 0.98 and 0.94, respectively), it had lower accuracy for PVC (correlation coefficients 0.92 for both parameters).

NiAlFe LTH /MoS2 p-n junction heterostructure composite as an effective visible-light-driven photocatalyst for enhanced degradation of organic dye under high alkaline conditions.

Designing of an effectual heterostructure photocatalyst for catalytic organic pollutant exclusion has been the subject of rigorous research intended to resolve the related environmental aggravation. Fabricating p-n junctions is an effective strategy to promote electron-hole separation of semiconductor photocatalysts as well as enhance the organic toxin degradation performance. In this study, a series of n-type NiAlFe-layered triple hydroxide (LTH) loaded with various ratios of p-type MoS2 was synthesized for forming a heterostructure LTH/MoS2 (LMs) by an in situ hydrothermal strategy. The photocatalysts were characterized by XRD, SEM&EDX, TEM, FT-IR, XPS, as well as UV-vis DRS. The photoactivity of photocatalysts was tested by the degradation of Indigo Carmine (IC) dye. The optimized catalyst (LM1) degrades 100% of indigo dye in high alkaline pH under UV light for 100 min. Besides, the degradation rate of LM1 is 15 times higher than that of pristine NiAlFe-LTH. The enhanced photoactivity is attributed to the synergistic effect between NiAlFe-LTH and MoS2 as well as the p-n junction formation.

Non-destructive monitoring and prediction of fouling by organic matters and residual anionic coagulant during membrane process.

Physical fouling characteristics on silicon carbide (SiC) membranes induced by various organic matter compounds vary depending on the presence of calcium ions (Ca2+). Both destructive techniques (morphological surface analysis) and non-destructive techniques (fouling properties monitoring) were used to determine the fouling mechanisms and behavior during the membrane filtration systems. Destructive analysis and a modified Hermia model were employed to assess the fouling mechanisms. Fouling behavior was also analyzed through non-destructive monitoring techniques including optical coherence tomography (OCT) and three-dimensional laser scanning confocal microscopy (3D-LSM). At concentrations of 10, 30, and 100 mg/L without Ca2+, the flux decreased by 57-95% for humic acid (HA) and anionic polyacrylamide (APAM). APAM exhibited a notable removal rate of up to 56% without Ca2+. At concentration of 10, 30, and 100 mg/L in the absence of Ca2+, the flux decreased by 6-8% for sodium alginate (SA). However, the addition of Ca2+ led to a reduction in the flux for SA by up to 91% and resulted in a removal rate of 40%. Furthermore, addition of Ca2+ led to an alteration of the fouling characteristics of HA and SA. In the case of HA, higher concentrations resulted in elevated thickness and roughness with correlation coefficients of 0.991 and 0.992, respectively. For SA, increased SA concentration led to a thicker (correlation coefficient of 0.999) but smoother surfaces (correlation coefficients of 0.502). Monitoring of these physical characteristics of the fouling layer through non-destructive analysis is crucial for effective fouling management, optimization of the system performance and extending the lifespan of the membrane. By continuously assessing the fouling layer thickness and surface roughness, we expect to be able to provide insights on the fouling behavior, identify trends, that can help scientists and engineers to make informed decisions regarding fouling control strategies in future.

Effect of NaOCl and ClO2 on seawater desalination using reverse osmosis with cartridge filtration as the pretreatment during the algal bloom.

Increased seawater temperature leads to harmful algal blooms (HABs), which releases toxic materials and extracellular polymeric substances (EPS) that are harmful to both humans and the environment. Reverse osmosis (RO) with cartridge filter (CF) as the pretreatment process is often used for desalination process. However, the EPS causes severe fouling on the CF, and RO membrane. Disinfectants, such as NaOCl and ClO2, are commonly used to remove biofouling, because they can oxidize and kill microorganisms. Therefore, our study aims to utilize NaOCl and ClO2 during the CF-RO process to minimize the algal growth within the system and minimize the fouling induced by EPS. Results from this study show that CF can remove more than 50% of protein and 14% of polysaccharides but is not effective in removing toxins. However, with disinfectants, toxic materials were completely oxidized. Improved removal of EPS with CF improved overall performance. The flux reduction in RO process without disinfection was over 60%, however, the flux decline was about 44% and 10% with NaOCl and ClO2, respectively. Both disinfectants were found to be effective, however use of ClO2 is recommended because it is less damaging the membrane, yet more effective in enhancing the performance.

Ultrahigh-porosity Ranunculus-like MgO adsorbent coupled with predictive deep belief networks: A transformative method for phosphorus treatment.

Phosphorus is a nonrenewable material with a finite supply on Earth; however, due to the rapid growth of the manufacturing industry, phosphorus contamination has become a global concern. Therefore, this study highlights the remarkable potential of ranunculus-like MgO (MO4-MO6) as superior adsorbents for phosphate removal and recovery. Furthermore, MO6 stands out with an impressive adsorption capacity of 596.88 mg/g and a high efficacy across a wide pH range (2-10) under varying coexisting ion concentrations. MO6 outperforms the top current adsorbents for phosphate removal. The process follows Pseudo-second-order and Langmuir models, indicating chemical interactions between the phosphate species and homogeneous MO6 monolayer. MO6 maintains 80 % removal and 96 % recovery after five cycles and adheres to the WHO and EUWFD regulations for residual elements in water. FT-IR and XPS analyses further reveal the underlying mechanisms, including ion exchange, electrostatic, and acid-base interactions. Ten machine learning (ML) models were applied to simultaneously predict multi-criteria (sorption capacity, removal efficiency, final pH, and Mg leakage) affected by 15 diverse environmental conditions. Traditional ML models and deep neural networks have poor accuracy, particularly for removal efficiency. However, a breakthrough was achieved by the developed deep belief network (DBN) with unparalleled performance (MAE = 1.3289, RMSE = 5.2552, R2 = 0.9926) across all output features, surpassing all current studies using thousands of data points for only one output factor. These captivating MO6 and DBN models also have immense potential for effectively applying in the real water test with error < 5 %, opening immense horizons for transformative methods, particularly in phosphate removal and recovery.

Fabricated magnetic adsorption - Forward osmosis membrane hybrid system for hydroponic irrigation from rich arsenic-containing heavy metal water stream.

Solidification of soluble arsenic from extremely acidic water and direct use of recovery water have been the major challenges in global water management, with the urgent need for new treatment system development. Thus, magnetic adsorption - fertilizer drawn forward osmosis (FDFO) hybrid system with a novel adsorbent and fertilizer mixture to solve the drawbacks of each process was developed with the ultimate goals of metal removal and direct reuse for hydroponic irrigation. Magnetic metal-organic framework-based adsorbent (CMM) was synthesized with various promising capabilities, i.e., wide pH range efficiency, strong pH adjustment, good stability, fast adsorption (1 h), and oxidation (40 min), high capacity (175 and 126 mg/g for As(III), As(V)), strong magnetization (75 emu/g), complete separation by a magnet, excellent interference-tolerance and reusability. In the FDFO system, a massive water volume (50 times higher than the initial draw solution with suitable nutrients for hydroponics irrigation with acceptable NaCl levels was obtained for the first time up to now. However, low As(III) rejection (50%) required the FDFO process to improve more. After integrating with magnetic adsorption, nearly 100% of As was removed. The pH of feed solutions adjusted from extremely acidic to close to neutral conditions further solidified metal by precipitation and membrane separation processes, leading to almost no detection of metals in the final draw solution. Also, favorable nutrients and excellent reusability were obtained. This hybrid process would generally offer an environmentally sustainable and high efficiency for decontaminating As-containing heavy metal water for hydroponic irrigation.

Nanobubbles in water and wastewater treatment systems: Small bubbles making big difference.

Since the discovery of nanobubbles (NBs) in 1994, NBs have been attracting growing attention for their fascinating properties and have been studied for application in various environmental fields, including water and wastewater treatment. However, despite the intensive research efforts on NBs' fundamental properties, especially in the past five years, controversies and disagreements in the published literature have hindered their practical implementation. So far, reviews of NB research have mainly focused on NBs' role in specific treatment processes or general applications, highlighting proof-of-concept and success stories primarily at the laboratory scale. As such, there lacks a rigorous review that authenticates NBs' potential beyond the bench scale. This review aims to provide a comprehensive and up-to-date analysis of the recent progress in NB research in the field of water and wastewater treatment at different scales, along with identifying and discussing the challenges and prospects of the technology. Herein, we systematically analyze (1) the fundamental properties of NBs and their relevancy to water treatment processes, (2) recent advances in NB applications for various treatment processes beyond the lab scale, including over 20 pilot and full-scale case studies, (3) a preliminary economic consideration of NB-integrated treatment processes (the case of NB-flotation), and (4) existing controversies in NBs research and the outlook for future research. This review is organized with the aim to provide readers with a step-by-step understanding of the subject matter while highlighting key insights as well as knowledge gaps requiring research to advance the use of NBs in the wastewater treatment industry.

Predicting the removal efficiency of pharmaceutical and personal care products using heated metal oxides as adsorbents based on their physicochemical characteristics.

Pharmaceutical and personal care products (PPCPs) are emerging pollutants that are commonly found in the environment and exist predominantly in nondegradable forms. Several attempts have been made to remove PPCPs via conventional wastewater treatment processes; however, these processes have limitations, such as high costs and insufficient removal efficiencies. Adsorption is a promising alternative for removing PPCPs because it is inexpensive, highly reusable, and easy to operate. Therefore, this study aims to determine the contributing characteristics that can be used to predict the adsorption behaviour of PPCPs based on their physicochemical properties, with heated metal oxide adsorbents (HMOAs). HAOP (heated aluminium oxide particles) and HIOP (heated iron oxide particles) with particle sizes below 38 µm were used. Results from the Brunauer-Emmett-Teller (BET) analysis show that HIOP has higher surface area and smaller pore size (113.7 ± 26.3 m2/g and 5.4 ± 1.8 nm) than HAOP (14.5 ± 0.6 m2/g and 18.6 ± 3.1 nm), which suggest that HIOP would show superior adsorption rates compared to HAOP. The adsorption mechanism is identified based on three major physicochemical properties of PPCPs: molecular weight (M.W.), octanol-water partition coefficient (log Kow), and acid dissociation constant (pKa). The results suggest that the most dominant factor that contributes to the adsorption of PPCPs on to HMOAs is the M.W., where the larger the molecular size, the better the adsorption efficiency. The tests conducted with varying log Kow values revealed that the hydrophilicity of the adsorbent influences the adsorption performance. It was found that HIOP exhibits better removal efficiencies with hydrophilic PPCPs (up to 83%) than with hydrophobic PPCPs (48%), while HAOP exhibits better removal efficiencies with hydrophobic PPCPs (86%) than with hydrophilic PPCPs, with less than 10% removal. Unlike the M.W. and pKa values, the log Kow does not exhibit any visible trend. Therefore, the adsorption behaviour can be predicted with the M.W. and pKa values of the PPCPs, when HAOP and HIOP are used as adsorbents.

An efficient data-driven desalination approach for the element-scale forward osmosis (FO)-reverse osmosis (RO) hybrid systems.

Freshwater shortages are a consequence of the rapid increase in population, and desalination of saltwater has gained popularity as an alternative water treatment method in recent years. To date, the forward osmosis-reverse osmosis (FO-RO) hybrid technology has been proposed as a low-energy and environmentally friendly next-generation seawater desalination process. Scaling up the FO-RO hybrid system significantly affects the success of a commercial-scale process. However, neither the ideal structure nor the membrane components for plate-and-frame FO (PFFO) and spiral-wound FO (SWFO) are known. This study aims to explore and optimize the performance of SWFO-RO and PFFO-RO hybrid element-scale systems in the desalination of seawater. The results showed that both hybrid systems could yield high water recovery under optimal operating conditions. The prediction of the system performance (water flux and reverse salt flux) by artificial intelligence was considerably better (R > 0.99, root mean square error <5%) than that of conventional mass balance models. A Markov-based decision tree successfully classified the water flux level in hybrid systems. An optimal set of operational conditions for each membrane system was proposed. For example, in RO, a combination of the feed solution (FS) flow rate (≥17.5 L/min), FS concentration (<17,500 ppm), and operation pressure (<35 bar) would result in high water permeability (>40 LMH). In addition, five SWFO elements and four PFFO elements should be the optimal numbers of FO membranes in the hybrid FO-RO system for effective seawater desalination, especially for long-term operation.

Effect of biocarriers on the nitrification and microbial community in moving bed biofilm reactor for anaerobic digestion effluent treatment.

The performance of a moving bed biofilm reactor (MBBR) depends largely on the type of biofilm carrier used. However, how different carriers affect the nitrification process, particularly when treating anaerobic digestion effluents, is not completely understood. This study aimed to evaluate the nitrification performance of two distinct biocarriers in MBBRs over a 140-d operation period, with a gradually decreasing hydraulic retention time (HRT) from 20 to 10 d. Reactor 1 (R1) was filled with fiber balls, whereas a Mutag Biochip was used for reactor 2 (R2). At an HRT of 20 d, the ammonia removal efficiency of both reactors was >95%. However, as the HRT was reduced, the ammonia removal efficiency of R1 gradually declined, ultimately dropping to 65% at a 10-d HRT. In contrast, the ammonia removal efficiency of R2 consistently exceeding 99% throughout the long-term operation. R1 exhibited partial nitrification, whereas R2 exhibited complete nitrification. Analysis of microbial communities showed that the abundance and diversity of bacterial communities, particularly nitrifying bacteria such as Hyphomicrobium sp. And Nitrosomonas sp., in R2 was higher than that in R1. In conclusion, the choice of biocarrier significantly impact the abundance and diversity of microbial communities in MBBR systems. Therefore, these factors should be closely monitored to ensure the efficient treatment of high-strength ammonia wastewater.

High-efficient and rapid removal of anionic and cationic dyes using a facile synthesized sole adsorbent NiAlFe-layered triple hydroxide (LTH).

It would be extremely momentous to familiarize a low-cost sole adsorbent NiAlFe-layered triple hydroxides (LTHs) having a strong sorption affinity towards both anionic and cationic dyes. Using the urea hydrolysis hydrothermal method LTHs were fabricated and by altering the ratio of participant metal cations the adsorbent was optimized. BET analysis revealed that the optimized LTHs possess an elevated surface area (160.04 m2/g) while TEM and FESEM analysis portrayed the stacked sheets-like 2D morphology. LTHs were employed for the amputation of anionic congo red (CR) and cationic brilliant green (BG) dye. The adsorption study showed that within 20 and 60 min, respectively, maximum adsorption capacities were achieved at 57.47 mg/g and 192.30 mg/g for CR and BG dye. Adsorption isotherm, kinetics, and thermodynamics study revealed that both chemisorptions with physisorptions were the assertive factor for the dye encapsulation. This enhanced adsorption performance of the optimized LTH for the anionic dye is attributed to its inherent anions exchange properties and new bond formation with the adsorbent skeleton. Whereas for the cationic dye, it was because of the formation of strong hydrogen bonds, and electrostatic interaction. Morphological manipulation of LTHs, formulates the optimized adsorbent LTH111, provokes the adsorbent for this elevated adsorption performance. Overall, this study revealed that LTHs have a high potential for the effectual remediation of dyes from wastewater as a sole adsorbent at a low cost.

Application of MnFe2O4 magnetic silica-covered ethylenediaminetetraacetic acid-functionalized nanomaterials to the draw solution in forward osmosis.

Forward osmosis (FO) is an emerging and promising water treatment technology. However, selection of an optimal draw solution (DS) is essential for efficient FO process operations. In this study, the potential of ethylenediaminetetraacetic acid (EDTA) functionalized SiO2-covered magnetic nanoparticles (MNPs) as DS in FO process were investigated. The MNPs were synthesized and characterized for their morphology, size distribution, magnetic behavior, and dispersibility. Investigations were carried out to determine the effects of DS concentration and MNPs type, utilizing bare, SiO2 covered, and EDTA coated MNPs at concentrations of 20, 40, and 60 g/L. Furthermore, water flux generation capability and rejection efficiency of octanoic acid (OC) was evaluated with EDTA-MNPs as DS in FO mode (active layer facing feed solution) and PRO mode (active layer facing draw solution). Our results showed that a maximum water flux of 9.59 ± 2 LMH in FO mode, and 11.104 ± 2 LMH in PRO mode was achieved using 60 g/L of EDTA-MNPs. Additionally, we investigated the reusability of the EDTA-coated MNPs and found that their recovery was higher than (>90%) with no aggregation. The stability of EDTA-MNPs was due to strong covalent linkages between their four carboxylate groups and the hydrophilic SiO2 surface layer, which resulted in steric hindrance and prevented their aggregation. Finally, we assessed the rejection efficiency of OC at different pH values and found that it was low (30-39%) at pH values below pKa and high (90-97%) at pH values above pKa. Owing to internal concentration polarization, the rejection of OC in FO mode was (10-20%) higher than in PRO mode. The findings demonstrate EDTA-coated MNPs have significant potentials as an effective DS in FO process .

Impact of pre-coagulation on the ceramic membrane process during oil-water emulsion separation: Fouling behavior and mechanism.

Coagulation has been evaluated as an economical and effective pre-treatment method for controlling membrane fouling. We investigated the influence of the pre-coagulation of oil-water (O/W) emulsions on the formation of membrane fouling in the ceramic membrane process. The results confirmed that pre-coagulation effectively mitigated the fouling formation on the ceramic membrane surface during the O/W emulsion separation. The mechanism of mitigating membrane fouling by pre-coagulation was proposed, owing to the reduction in the zeta potential value of oil droplets by pre-coagulation, resulting in weak electrostatic attraction between oil droplets and ceramic membrane surfaces, and an increase in the size of the oil droplets by pre-coagulation, leading the formation of a cake layer fouling. In addition, the decrease in the hydrophobicity of oil droplets by pre-coagulation resulted in alleviating the hydrophobic interaction between oil droplets and membrane surface. The proposed fouling mechanism was supported by the characterization of the virgin and fouled membrane surfaces and the analysis of the fouling resistance ability of the membranes. Our study could be indicative of mitigation protocols that can be used to alleviate membrane fouling on ceramic membranes during oily wastewater treatment.

Efficient one-pot synthesis of magnetic MIL-100(Fe) using nitric acid without additional Fe ion addition and adsorption behavior of charged organic compounds.

Metal organic frameworks (MOFs) are attracting attention as high-performance adsorbents because of their high specific surface area and porosity. In particular, magnetic MIL-100(Fe) has the both characteristics of Fe3O4 and MIL-100(Fe), which are magnetic characteristics, high specific surface area and open metal sites. However, multiple synthetic steps are required for synthesis of magnetic MOF, and there is limitation that the residual organic linker and unreacted Fe center ions can be discharged, and they cause water pollution. In this study, magnetic MIL-100(Fe) was synthesized within 4 h without the addition of Fe ions by using nitric acid for the surface modification of Fe3O4. Magnetic MIL-100(Fe) was confirmed through XRD, FTIR, and TEM surface analysis, and the optimal conditions for nitric acid addition were selected through magnetization measurements and BET analysis of synthesized magnetic MIL-100(Fe). Thereafter, adsorption evaluation was performed using MB and MO, which are representative cationic and anionic dyes, respectively. The pseudo-second-order Langmuir model showed a relatively high correlation compared to the other models. This shows that the adsorption mechanism depends on both the amount of adsorbent and adsorbate, and Fe3O4 modification with nitric acid does not cause any change in the adsorption mechanism. In the case of adsorption selectivity between the MB and MO, removal rates of 93.27% and 58.73% were obtained, respectively. The above results can contribute to the simplification of the manufacturing of magnetic metal organic frameworks for removing ionic organic compounds and the minimization of water pollution in the manufacturing process.

Ionic fluid as a novel cleaning agent for the control of irreversible fouling in reverse osmosis membrane processes.

While a variety of chemical cleaning strategies has been studied to control fouling in membrane-based water treatment processes, the removal of irreversible foulants strongly bound on membrane surfaces has not been successful. In this study, we firstly investigated the diluted aqueous solutions of ionic fluid (IF, 1-ethyl-3-methylimidazolium acetate) as a cleaning agent for three model organic foulants (humic acid, HA; bovine serum albumin, BSA; sodium alginate, SA). The real-time monitoring of cleaning progress by optical coherence tomography (OCT) showed that fouling layer was dramatically swelled by introducing IF solution and removed by shear force exerted during cleaning. This phenomenon was induced due to the pre-existing interactions between organic foulants were weakened by the intrusion of IF into the fouling layer, which was analyzed by the measurement of adhesion forces using atomic force microscopy (AFM). In the experiments with model foulants and wastewater effluent, IF was added to alkaline cleaning agents (NaOH) to verify the applicability to be supplemented in commercial cleaning agents, and resulted in the significantly enhanced control of irreversible membrane fouling. Implication of utilizing recyclable IF with negligible volatility is that environmental effects of membrane cleaning solutions could be minimized by decreasing usage of cleaning chemicals, while increasing the cleaning efficiency.

Prediction of forward osmosis membrane engineering factors using artificial intelligence approach.

Currently, forward osmosis (FO) is widely studied for wastewater treatment and reuse. However, there are still challenges which need to be addressed for the application of the FO on a commercial scale. In the meantime, with a strong capability to solve the complicated nonlinear relationships and to examine of the relations between multiple variables, artificial intelligence (AI) technique could be a viable tool to improve FO system performance to make it more applicable. This study aims to develop an AI-based model for supporting early control and making decision in the FO membrane system. The results show that the artificial neural networks model is extremely suitable for prediction of water flux, membrane fouling, and removal efficiencies. The most appropriate input dataset for the model was proposed, in which organic matters, sodium ion, and calcium ion concentrations played a vital role in all predictions. The best model architecture was suggested with an optimal hidden layers (2-4 layers), and neurons (10-15 neurons). The developed models for membrane fouling show strong correlation between experimental and predicted data (with R2 values for prediction of membrane fouling porosity, thickness, roughness, and density were 0.85, 0.97, 0.97, and 0.98, respectively). The prediction of water flux presented a high R2 and low root mean square error (RMSE) of 0.92 and 0.9 L m-2.h-1, respectively. Prediction of the contaminant removal exhibits a relatively high correlation between the observed and predicted data with R2 values of 0.87 and RMSE values of below 2.7%. The developed models are expected to create a breakthrough in the control and enhancement in a novel FO membrane process used for wastewater treatment by providing us with actionable insights to produce fit-for-future systems in the context of sustainable development.