Highly efficient simultaneous ultrasonic assisted adsorption of brilliant green and eosin B onto ZnS nanoparticles loaded activated carbon: Artificial neural network modeling and central composite design optimization

Using predictive models unravel the potential of titanium oxide-loaded activated carbon for the removal of leachate ammoniacal nitrogen

The TiO2 nanocomposite efficiency was determined under optimized conditions with activated carbon to remove ammoniacal nitrogen (NH3-N) from the leachate sample. In this work, the facile impregnation and pyrolysis synthesis method was employed to prepare the nanocomposite, and their formation was confirmed using the FESEM, FTIR, XRD, and Raman studies. In contrast, Raman phonon mode intensity ratio ID/IG increases from 2.094 to 2.311, indicating the increase of electronic conductivity and defects with the loading of TiO2 nanoparticles. The experimental optimal conditions for achieving maximum NH3-N removal of 75.8% were found to be a pH of 7, an adsorbent mass of 1.75 mg/L, and a temperature of 30 °C, with a corresponding time of 160 min. The experimental data were effectively fitted with several isotherms (Freundlich, Hill, Khan, Redlich-Peterson, Toth, and Koble-Corrigan). The notably elevated R2 value of 0.99 and a lower ARE % of 14.61 strongly support the assertion that the pseudo-second-order model compromises a superior depiction of the NH3-N reduction process. Furthermore, an effective central composite design (CCD) of response surface methodology (RSM) was employed, and the lower RMSE value, precisely 0.45, demonstrated minimal disparity between the experimentally determined NH3-N removal percentages and those predicted by the model. The subsequent utilization of the desirability function allowed us to attain actual variable experimental conditions.

Ultrasonic treatment of dye chemicals in wastewater: A review

The existence of pollutants, such as toxic organic dye chemicals, in water and wastewater raises concerns as they are inadequately eliminated through conventional water and wastewater treatment methods, including physicochemical and biological processes. Ultrasonic treatment has emerged as an advanced treatment process that has been widely applied to the decomposition of recalcitrant organic contaminants. Ultrasonic treatment has several advantages, including easy operation, sustainability, non-secondary pollutant production, and saving energy. This review examines the elimination of dye chemicals and categorizes them into cationic and anionic dyes based on the existing literature. The objectives include (i) analyzing the primary factors (water quality and ultrasonic conditions) that influence the sonodegradation of dye chemicals and their byproducts during ultrasonication, (ii) assessing the impact of the different sonocatalysts and combined systems (with ozone and ultraviolet) on sonodegradation, and (iii) exploring the characteristics-based removal mechanisms of dyes. In addition, this review proposes areas for future research on ultrasonic treatment of dye chemicals in water and wastewater.

Sonoactivated Nanomaterials: A potent armament for wastewater treatment

The world is currently facing a critical issue of water pollution, with wastewater being a major contributor. It comes from different types of pollutants, including industrial, medical, agricultural, and domestic. Effective treatment of wastewater requires efficient degradation of pollutants and carcinogens prior to discharge. Commonly used methods for wastewater treatment include filtration, adsorption, biodegradation, advanced oxidation processes, and Fenton oxidation, among others.The sonochemical effect refers to the decomposition, oxidation, reduction, and other reactions of pollutant molecules in wastewater upon ultrasound activation, achieving pollutants removal. Furthermore, the micro-flow effect generated by ultrasonic waves creates tiny bubbles and eddies. This significantly increases the contact area and exchange speed of pollutants and dissolved oxygen, thereby accelerating pollutant degradation. Currently, ultrasonic-assisted technology has emerged as a promising approach due to its strong oxidation ability, simple and cheap equipments, and minimal secondary pollution. However, the use of ultrasound in wastewater treatment has some limitations, such as high energy consumption, lengthy treatment time, limited water treatment capacity, stringent water quality requirements, and unstable treatment effects. To address these issues, the combination of enhanced ultrasound with nanotechnology is proposed and has shown great potential in wastewater treatment. Such a combination can greatly improve the efficiency of ultrasonic oxidation, resulting in an improved performance of wastewater purification. This article presents recent progress in the development of sonoactivated nanomaterials for enhanced wastewater disposal. Such nanomaterials are systematically classified and discussed. Potential challenges and future prospects of this emerging technology are also highlighted.

Ionic Liquid Cross-Linked High-Absorbent Polymer Hydrogels: Kinetics of Swelling and Dye Adsorption

The use of polymer gels for the removal of toxic chemicals from wastewater is an important area in terms of both academic and industrial research. This work presents a simple approach to the fabrication of chemically cross-linked cationic hydrogel adsorbents using designed ionic liquid-based cross-linkers and their successful use in the removal of organic dyes. Two different ionic liquid cross-linkers, [VIm-4VBC][Cl] (ILA)/[DMAEMA-4VBC][Cl] (ILB), are synthesized by the simple nucleophilic substitution reaction of 4-vinylbenzyl chloride (4VBC) separately with 1-vinylimidazole (VIm) and 2-(dimethylamino)ethyl methacrylate (DMAEMA). Cross-linked poly(acrylamide) (CPAam) and poly(2-hydroxyethyl methacrylate) (CPHEMA) hydrogels are then prepared from the corresponding monomers and as-synthesized cross-linkers (ILA and ILB) by free radical polymerization in the presence of a redox initiator combining ammonium persulfate (APS) and N,N,N',N'-tetramethylethylenediamine (TEMED). The dried CPAam and CPHEMA xerogels exhibit macroporous morphology and high thermal stability. The hydrogel samples exhibit high swelling behavior, and the diffusion of water molecules into the hydrogels follows pseudo-Fickian kinetics. The cationic cross-linking sites in the hydrogel networks allow preferable binding with anionic dyes, and these dye uptake capacities are determined using different model anionic dyes via UV-vis spectroscopy. The dye adsorption onto these hydrogels follows a pseudo-second-order kinetic model. The adsorption mechanism is also analyzed by employing intraparticle diffusion and Boyd kinetic models. The relationship between the maximum equilibrium adsorption capacity (q_m) of the hydrogels for eosin B (EB) dye and the equilibrium EB concentration can be better described by Langmuir and Freundlich isotherm models, and the estimated q_m using the Langmuir isotherm can reach more than 100 mg g^-1. The cross-linked hydrogels can be easily regenerated and have a recycling efficiency of >80% for up to three consecutive dye adsorption-desorption cycles, which is promising for their use in wastewater treatment.

Application of response surface methodology and box-behnken design for the optimization of mercury removal by Ulva sp

Mercury (Hg) is a global and top priority contaminant, toxic at low concentrations. Although it has been progressively eliminated from processes, this metal continues to circulate in the atmosphere, soil, and water. In this work, the Response Surface Methodology (RSM) combined with a Box-Behnken Design (3 factors - 3 levels) was used to optimize key operational conditions that influence the removal and uptake of Hg by living macroalga Ulva sp. in a complex mixture containing several elements used in industry (potentially toxic elements, rare earth elements, and platinum-group elements) (initial concentration 10, 100 and 190 µg/L, salinity 15, 25 and 35, seaweed stock density 1.0, 3.0 and 5.0 g/L). Results evidenced the great capability of Ulva sp. to remove Hg, with removal efficiencies between 69 % and 97 %. 3-D surfaces showed that the most impactful variable was seaweed stock density, with higher densities leading to higher removal. Regarding the uptake, a positive correlation between initial concentration and q_t values was observed. The appliance of RSM made possible to obtain optimal operating conditions for removing virtually 100 % of Hg from waters with high ionic strength, which is a pivotal step in the direction of the application of this remediation biotechnology at large scale.

Design of an S-scheme photo-catalyst utilizing a Cu-doped perovskite and MOF-5 for simultaneous degradation of organic pollutants under LED light irradiation: Application of EXRSM method for spectra separation and BBD-RSM modeling

Heterojunction photo-catalysts have attracted significant attention in solar energy conversion due to their ability to reduce suppressing electron-hole pairs and improve catalytic capability. Herein, we designed an S-scheme photo-catalyst by encapsulating a Cu-doped perovskite inside the pores of MOF-5 for the first time, exhibiting excellent efficiency in a pollutant degradation process. The pristine MOF cannot act in the visible light region because of its wide bandgap. However, the encapsulation modified its bandgap and but also increased its photo-catalytic activity. Simultaneous photo-degradation of two organic contaminants, methylene blue (MB) and paracetamol (PA), was investigated to evaluate the catalytic activity of this composite. As a challenge, the UV-vis spectra of PA strongly overlapped with MB in a binary mixture preventing direct measurement of its concentration without previous separation via conventional methodologies. Hence, we used a simple and fast technique called the extended ratio subtraction method (EXRSM) to separate their absorption spectra. The statistical investigations established that it could resolve the issue of signal overlapping. Also, a statistical approach, Box-Behnken (BBD-RSM), was used to model and optimize the degradation process providing a better way to explain the effect and interactions of main parameters on degradation efficiency. Now, an empirical model for each pollutant can make a relationship between them. The photo-degradation yield was obtained at 67.12% and 87.96% for PA and MB, respectively, under optimum conditions. Furthermore, the kinetics and mechanism of reaction were investigated, and the results revealed that it follows a pseudo-first-order model for each pollutant.

A Novel Symmetrical Peak Fitting Method Based on Improved WOA Algorithm for the Analysis of Microchip Electrophoresis Signals

The problem of overlapping peaks has been a challenge in microchip electrophoresis (ME) signal analysis. However, traditional peak fitting algorithms have difficulty analyzing overlapping peaks due to the high dependence on the starting point. In this study, we propose a symmetrical peak fitting method named the tent-mapped whale optimization algorithm and Levenberg–Marquardt (TWOALM), which combines a whale optimization algorithm (WOA) improved by one of the most commonly used chaotic maps, the tent map and the Levenberg–Marquardt (LM) algorithm. Specifically, we first derive the fitted model for the overlapping peaks, showing that it is separable nonlinear least squares, significantly reducing the number of parameters to be optimized. Second, we integrate the tent map into the WOA, which improves the convergence speed of the peak fitting algorithm. Finally, we propose an efficient peak-fitting algorithm that combines the improved WOA and LM. The advantage of the proposed algorithm is that it is significantly faster than WOA and significantly more accurate than the LM algorithm. The results of fitting the synthetic peaks and ME signals showed that the combination of the chaotic map-based WOA algorithm and the LM algorithm can significantly improve the peak fitting performance and provide an effective solution for the analysis of overlapping peaks.

Ultrasound-assisted adsorption on porous ceramic for removal of iron in water

This study proposes the use of an ultrasound-assisted adsorption system coupled to porous ceramic fragments to improve the removal of iron from FeSO₄ aqueous solution. Ultrasound was applied using an ultrasound bath at a low frequency (37 kHz, 330 W). The optimized conditions for Fe removal were achieved by 7 g of adsorbent, 40 min of sonication, 20 mg L^-1 of initial Fe concentration, and 30 °C of reaction temperature. After optimizing the conditions, the method was applied for the removal of iron in groundwater. A central composite design and response surface methodology were used to evaluate the degree to which different variables had a significant effect on iron removal. The efficiency of iron removal using the selected conditions for FeSO₄ solution was near to 100%. However, for groundwater samples, the maximum iron removal efficiencies of the system with and without ultrasound were 80.7% and 51.1%, respectively, indicating that the adsorption with ultrasound was significantly higher than that without ultrasound. It was shown that the proposed ultrasound-assisted adsorption system can be used to enhance the removal of inorganic iron from groundwater.

A Review of the Modeling of Adsorption of Organic and Inorganic Pollutants from Water Using Artificial Neural Networks

The application of artificial neural networks on adsorption modeling has significantly increased during the last decades. These artificial intelligence models have been utilized to correlate and predict kinetics, isotherms, and breakthrough curves of a wide spectrum of adsorbents and adsorbates in the context of water purification. Artificial neural networks allow to overcome some drawbacks of traditional adsorption models especially in terms of providing better predictions at different operating conditions. However, these surrogate models have been applied mainly in adsorption systems with only one pollutant thus indicating the importance of extending their application for the prediction and simulation of adsorption systems with several adsorbates (i.e., multicomponent adsorption). This review analyzes and describes the data modeling of adsorption of organic and inorganic pollutants from water with artificial neural networks. The main developments and contributions on this topic have been discussed considering the results of a detailed search and interpretation of more than 250 papers published on Web of Science ® database. Therefore, a general overview of the training methods, input and output data, and numerical performance of artificial neural networks and related models utilized for adsorption data simulation is provided in this document. Some remarks for the reliable application and implementation of artificial neural networks on the adsorption modeling are also discussed. Overall, the studies on adsorption modeling with artificial neural networks have focused mainly on the analysis of batch processes (87%) in comparison to dynamic systems (13%) like packed bed columns. Multicomponent adsorption has not been extensively analyzed with artificial neural network models where this literature review indicated that 87% of references published on this topic covered adsorption systems with only one adsorbate. Results reported in several studies indicated that this artificial intelligence tool has a significant potential to develop reliable models for multicomponent adsorption systems where antagonistic, synergistic, and noninteraction adsorption behaviors can occur simultaneously. The development of reliable artificial neural networks for the modeling of multicomponent adsorption in batch and dynamic systems is fundamental to improve the process engineering in water treatment and purification.

Green synthesis of zinc oxide nanoparticles loaded on activated carbon prepared from walnut peel extract for the removal of Eosin Y and Erythrosine B dyes from aqueous solution: experimental approaches, kinetics models, and thermodynamic studies

Water contamination due to release of dye containing effluents is one of the environmental problems of serious concern today. The present study investigate the green synthesis of zinc oxide nanoparticles (ZnO-NPs) doped on activated carbon (AC) prepared from walnut peel extract and to estimate its efficiency in the removal of Eosin Y (Eo-Y) and Erythrosine B (Er-B) from its aqueous solution. The synthesized AC-ZnO was identified by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and the Brunauer-Emmett-Teller. The influence of various parameters such as pH, dosage of AC-ZnO, contact time, and concentrations of Eo-Y and Er-B was also studied. The pH 3 was observed as the optimum pH while the equilibrium was noticed to reach in 30 min at dosage of 1 g/L and initial concentration 100 mg/L for Eo-Y and Er-B adsorption onto AC-ZnO. The maximum adsorption capacity of Eo-Y and Er-B onto AC-ZnO was found to be 163.9 and 144.92 mg/g (and removal efficiencies of 95.11 and 98.31 %), respectively. The process of Eo-Y and Er-B adsorption on AC-ZnO was observed to be depended on the pseudo-second-order kinetic model which indicates chemisorption processes. Langmuir adsorption isotherm model test described the removal of Eo-Y and Er-B on AC-ZnO. The thermodynamic data indicated that the adsorption was endothermic process. Also, the values, S_BET and V_TOTAL, for the AC-ZnO were equal to 725.65 m²/g and 0.6004 cm³/g, respectively. The results of this study exhibited that AC-ZnO was a very effective method that can be used for the removal of Eo-Y and Er-B from aqueous solutions.

Experimental and Density Functional Theory Studies on a Zinc(II) Coordination Polymer Constructed with 1,3,5-Benzenetricarboxylic Acid and the Derived Nanocomposites from Activated Carbon

A coordination polymer with the composition C₁₂H₂₀O₁₆Zn₂ (ZnBTC) (BTC = benzene-1,3,5-tricarboxylate) was synthesized under hydrothermal conditions at 120 °C, and its crystal structure was determined using single-crystal X-ray crystallography. First-principles electronic structure investigation of the compound was carried out using the density functional theory computational approach. The highest occupied molecular orbital, the lowest unoccupied molecular orbital, the energy gap, and the global reactivity descriptors of ZnBTC were investigated in both the gas phase and the solvent phase using the implicit solvation model, while the donor-acceptor interactions were studied using natural bond orbital analyses. The results revealed that ZnBTC is more stable but less reactive in solvent medium. The larger stabilization energy E ⁽²⁾ indicates a greater interaction of ZnBTC in the solvent than in the gas phase. Orange peel activated carbon and banana peel activated carbon chemically treated with ZnCl₂ and/or KOH were used to modify the synthesis of ZnBTC to obtain nanocomposites. ZnBTC and the nanocomposites were characterized by powder X-ray diffraction (PXRD), thermogravimetric analysis, and Fourier transform infrared. The specific surface area (S _BET) and the average pore diameter of the materials were determined by nitrogen sorption measurements using the Brunauer-Emmett-Teller (BET) method, while scanning electron microscopy and transmission electron microscopy were used to observe their morphology and particle size, respectively. The PXRD of all the activated carbon materials exhibited peaks at 2θ values of 12.7 and 13.9° corresponding to a d-spacing of 6.94 and 6.32 Å, respectively. The N₂ adsorption-desorption isotherm of the materials are of type II with nanocomposites showing enhanced S _BET compared to the pristine ZnBTC. The results also revealed that activated carbons from the banana peel and the derived nanocomposites exhibited better porous structure parameters than those obtained from orange peel. The degradation efficiency of methyl orange in aqueous solutions using ZnBTC as a photocatalyst was found to be 52 %, while that of the nanocomposites were enhanced up to 79 %.

Sonochemical fabrication of inorganic nanoparticles for applications in catalysis

Catalysis covers almost all the chemical reactions or processes aiming for many applications. Sonochemistry has emerged in designing and developing the synthesis of nano-structured materials, and the latest progress mainly focuses on the synthetic strategies, product properties as well as catalytic applications. This current review simply presents the sonochemical effects under ultrasound irradiation, roughly describes the ultrasound-synthesized inorganic nano-materials, and highlights the sonochemistry applications in the inorganics-based catalysis processes including reduction, oxidation, degradation, polymerization, etc. Or all in all, the review hopes to provide an integrated understanding of sonochemistry, emphasize the great significance of ultrasound-assisted synthesis in structured materials as a unique strategy, and broaden the updated applications of ultrasound irradiation in the catalysis fields.

Treatment of malachite green dye containing solution using bio-degradable Sodium alginate/NaOH treated activated sugarcane baggsse charcoal beads: Batch, optimization using response surface methodology and continuous fixed bed column study

In this study, carbonized material was produced using sodium hydroxide treated Sugar cane bagasse (SB), and synthesized materials ware used to prepare Sodium Alginate/SBAC composite beads which were further used as an adsorbent to remove malachite green dye (MG) present in water. Physiochemical characteristics of composite beads were analyzed using FTIR, SEM, TGA, and BET. Adsorption equilibrium data showed excellent fit to the Freundlich model (R² = 0.994) than to the Langmuir model (R² = 0.925). Adsorption kinetics study indicated that the MG removal process would be better described by the pseudo-second-order kinetic model. The thermodynamic study suggested the spontaneous and endothermic nature of MG adsorption. By using response surface methodology, the optimum conditions for MG adsorption on composite beads were found to be 115.43 min, 0.3 g/L and pH 8 for contact time, adsorbent mass, and pH respectively and MG adsorption efficiency was 97.88%. The fixed-bed column data were evaluated using several kinetic models and among them, Thomas model showed the best agreement with investigation results. These results revealed that synthesized composite beads have a high affinity toward MG and it could be reasonable, eco-friendly adsorbent for dye removal from wastewater.

Biosorption of Congo Red from Aqueous Solutions Based on Self-Immobilized Mycelial Pellets: Kinetics, Isotherms, and Thermodynamic Studies

In the current study, Aspergillus fumigatus and Pseudomonas putida were co-cultured to obtain self-immobilized mycelial pellets to evaluate the decolorization efficiency of Congo red (CR). The obtained co-culture exhibited the highest decolorization efficiency of 99.22% compared to monoculture of A. fumigatus (89.20%) and P. putida (55.04%). The morphology and surface properties of the mycelial pellets were characterized by SEM, FTIR, BET, and XPS. The adsorption kinetics and isotherms were well described by pseudo-second-order and Langmuir models. The findings revealed that the removal efficiency of the mycelial pellet for CR was significantly influenced by physicochemical parameters. Thermodynamic result showed that the biosorption process was endothermic. The maximum adsorption capacity can be obtained from the Langmuir model, which is 316.46 mg/g, it suggests that mycelial pellet was an efficient biosorbent to remove CR from aqueous solution. This study indicates that the mycelial pellet can develop a sustainable approach to eliminate CR from the wastewater.

Brilliant Green Dye Biosorption Using Activated Carbon Derived from Guava Tree Wood

The removal of brilliant green (BG) dye from an aqueous solution using activated carbon (AC) derived from guava tree wood is conducted in batch conditions. The influence of different factors such as contact time, pH, adsorbent dosage, initial dye concentration, and temperature on the adsorption of BG onto AC was investigated. FTIR, BET, and SEM analyses were performed to determine the characteristics of the material. The isotherm results were analyzed using the Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich isotherms. Linear regression was used to fit the experimental data. It was found that the equilibrium data are best represented by the Freundlich isotherm, and the adsorption capacity (qe) was 90 mg dye/g AC. The values of the free energy (∆G), enthalpy (∆H), and entropy (∆S) were −86.188 kJ/mol, 43.025 kJ/mol, and 128 J/mol.K, respectively, at pH 7 for the BG dye. The kinetics of BG dye adsorption were analyzed using pseudo-first-order and pseudo-second-order models, and it was found that the pseudo-second-order model was suitable for the behavior of the BG dye at R2 = 0.999.

Optimization of ultrasound-assisted extraction of polyphenols from wheatgrass (Triticum aestivum L.)

Conventional extraction techniques require high consumption of available resources and thus are ineffective and expensive, especially at an industrial scale. The aim of the study was to optimize the ultrasound-assisted extraction of polyphenols from fresh wheatgrass (Triticum aestivum L.). The effects of different extraction techniques and solvents were investigated on the yield of extractive substances and antioxidant activity. The ultrasound-assisted extraction technique and ethanol gave the highest yield of extractive substances so that they were used in the optimization studies. The central composite design was employed to find the optimal levels of ethanol concentration, extraction temperature, and extraction time. The total phenolic content was varied in the range of 10.50-15.50 grams of gallic acid equivalents per 100 g of dry weight of plant material (g GAE 100 g^-1 dw). The optimal conditions for ultrasound-assisted extraction were: (1) 56% (v/v) ethanol, (2) temperature of 59 °C, and (3) extraction time of 28 min. The results of ANOVA indicated that the highest impact had the extraction temperature on the total phenolic content. The toxic solvents were not used in the developed extraction procedure. The consumption of energy and raw plant material is estimated to be lower by at least 10% compared to conventional techniques.

Interfacial separation of concentrated dye mixtures from solution with environmentally compatible nitrogenous-silane nanoparticles modified with Helianthus annuus husk extract

The capacity of an adsorbent to bind and remove dye from solution greatly depends on the type of functionalization present on the nanoparticles surface, and its interaction with the dye molecules. Within this study, nitrogenous silane nanoparticles were hydrothermally synthesized resulting in the formation of rapid and highly efficient adsorbents for concentrated mixed dyes. The amorphous silane nanoparticles exhibited a monolayer based mechanism of mixed dye adsorption with removal capacities between 416.67 and 714.29 mg/g of adsorbent. Dye removal was predominantly due to the electrostatic attraction between the positively charged silane nanoparticles (13.22-8.20 mV) and the negatively charged dye molecules (-54.23 mV). Addition of H. annuus extract during synthesis resulted in three times the surface area and 10 times increased pore volume compared to the positive control. XPS analysis showed that silane treatments had various nitrogen containing functionalities at their surface responsible for binding dye. The weak colloidal stability of silane particles (13.22-8.20 mV) was disrupted following dye binding, resulting in their rapid coagulation and flocculation which facilitated the separation of bound dye molecules from solution. The suitability for environmental applications using these treatments was supported by a bacterial viability assay showing >90% cell viability in treated dye supernatants.

Tackling environmental challenges in pollution controls using artificial intelligence: A review

This review presents the developments in artificial intelligence technologies for environmental pollution controls. A number of AI approaches, which start with the reliable mapping of nonlinear behavior between inputs and outputs in chemical and biological processes in terms of prediction models to the emerging optimization and control algorithms that study the pollutants removal processes and intelligent control systems, have been developed for environmental clean-ups. The characteristics, advantages and limitations of AI methods, including single and hybrid AI methods, were overviewed. Hybrid AI methods exhibited synergistic effects, but with computational heaviness. The up-to-date review summarizes i) Various artificial neural networks employed in wastewater degradation process for the prediction of removal efficiency of pollutants and the search of optimizing experimental conditions; ii) Evaluation of fuzzy logic used for intelligent control of aerobic stage of wastewater treatment process; iii) AI-aided soft-sensors for precisely on-line/off-line estimation of hard-to-measure parameters in wastewater treatment plants; iv) Single and hybrid AI methods applied to estimate pollutants concentrations and design monitoring and early-warning systems for both aquatic and atmospheric environments; v) AI modelings of short-term, mid-term and long-term solid waste generations, and various ANNs for solid waste recycling and reduction. Finally, the future challenges of AI-based models employed in the environmental fields are discussed and proposed.

Enhanced visible light photocatalytic degradation of dyes in aqueous solution activated by HKUST-1: performance and mechanism

HKUST-1 is a copper-based metal–organic framework (MOF) and potential photocatalyst, but minimal research has addressed the performance and mechanism of HKUST-1 in the visible light photocatalytic degradation of dyes. In the present work, HKUST-1 was applied as a photocatalyst to activate peroxomonosulfate (PMS) under visible light (Vis) for dye removal in aqueous solution. The results showed that the removal efficiency of two cationic dyes [rhodamine B (RhB) and methylene blue (MB)] was greater than 95% within 120 min. Free radicals such as SO₄⁻˙, ·OH were present in the degradation process, with SO₄⁻˙ playing a dominant role. Zeta potential, X-ray photoelectron spectroscopy, and photoluminescence spectroscopy data were used to investigate the degradation mechanism. In the degradation process, surface charge attraction between HKUST-1 and cationic dyes promotes removal efficiency, with the degradation efficiency of cationic dyes (MB and RhB) more than 50% higher than for anionic dyes [acid orange 7 (AO₇) and methyl red (MR)]. On the other hand, HKUST-1 has been proved to activate PMS by conducting photoelectrons, which accelerated the degradation of dyes. Compared with the reaction conditions of PMS/Vis, when the HKUST-1 was present (HKUST-1/PMS/Vis), the degradation rates of MB and RhB increased by 62.7 and 63.2%, respectively.

HKUST-1 is a copper-based metal–organic framework (MOF). The HKUST-1/PMS/Vis system can effectively degrade RhB and MB but accomplish poor removal of AO₇ and MR, which is attributed to the repulsion between surface charges.

A review of the application of sonophotocatalytic process based on advanced oxidation process for degrading organic dye

Nowadays the use of conventional wastewater treatment methods is becoming increasingly challenging mainly due to the presence of organic matter in wastewater. Therefore, an emerging technology is needed to deal with these highly concentrated and toxic non-biodegradable organic matters. In the last few decades, advanced oxidation process (AOP) has emerged to treat wastewaters discharged from industries. Recently, researchers have shown interest to use the application of ultrasound (US) in photocatalysis, i.e. sonophotocatalysis, to improve the performance of the treatment process in the degradation of organic and inorganic contaminants in aqueous streams. Sonophotocatalysis is the combination of the use of ultraviolet (UV) and US.

Application of EDTA modified Fe3O4/sawdust carbon nanocomposites to ameliorate methylene blue and brilliant green dye laden water

This work explored the potential of magnetic sawdust carbon nanocomposites for cationic dyes removal from aqueous medium. EDTA modified magnetic sawdust carbon nanocomposites (EDTA@Fe₃O₄/SC ncs) were prepared by biogenic green reduction and precipitation approach. The surface properties, structure and composition of nanocomposites were characterized by HRTEM, FESEM, XRD, EDX, BET, FTIR etc. The Fe₃O₄ nanoparticles were 10-20 nm in diameters and having 14 m²/g surface area. Removal of Methylene blue (MB) and Brilliant green (BG) dyes from aqueous medium was studied in batch mode experiments. The maximum removal was achieved at neutral pH 7.0 with in 30 min. Adsorption capacity of EDTA@Fe₃O₄/SC for MB and BG dyes was 227.3 mg/g and 285.7 mg/g, respectively. Dye adsorption behaviour is well explained by Freundlich model. The rate of cationic dye adsorption is explained by pseudo-second order model. The value of thermodynamic parameters confirmed that adsorption process was spontaneous and favourable. Desorption and reusable efficiency of nanocomposites was also evaluated.

Synergistic effects and kinetics of rGO-modified TiO2 nanocomposite on adsorption and photocatalytic degradation of humic acid

Graphene oxide was prepared using the modified Hummers method and reduced graphene oxide (rGO) - titanium dioxide (TiO₂) nanocomposite was synthesised using the one-step hydrothermal treatment. The synergistic effects on adsorption and photocatalytic properties of the rGO-TiO₂ nanocomposite for the humic acid removal were systematically investigated. The results of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Raman and infrared (IR) spectroscopy indicate that GO was partially reduced to reduced graphene oxide (rGO) in the hydrothermal synthesis process and anatase TiO₂ nanoparticles uniformly grew on the surface of rGO. The photoelectron and photohole generated under visible light irradiation were effectively separated on the surface of rGO-TiO₂. The rGO-TiO₂ nanocomposite exhibited higher photocatalytic activity as a result of the synergistic effects of surface functional groups for adsorption and the excellent conductivity for photocatalytic reaction. The effect of rGO-TiO₂ nanocomposite dosage, light intensity and system temperature on the removal of humic acid solution was investigated. The results show that the removal efficiency of humic acid increased with system temperature and light intensity. When the dosage of rGO-TiO₂ nanocomposite was 1.2 g/L, the temperature, the light intensity and the pH of this system was 303 K, 4.37 Wm^-2 and 7, respectively, the removal efficiency of humic acid reached 88.7% under visible light irradiation.

Ultrasound wave assisted adsorption of congo red using gold-magnetic nanocomposite loaded on activated carbon: Optimization of process parameters

In this study, gold-magnetic nanocomposite in the presence of ultrasound wave assisted was synthesized and loaded on activated carbon (Au-Fe₃O₄-NCs-AC) by simple, fast and low-cost process. This novel material was applied for ultrasound assisted adsorption of congo red (CR) as model of toxic and even carcinogenic substance from aqueous solution. The detail of morphology and identity of Au-Fe₃O₄-AC was characterized by SEM and TEM techniques and correlation among response to variables such as pH (2-10), adsorbent mass (0.005-0.025 g), initial CR concentration (10-30 mg L^-1) and ultrasound time (2-6 min) was investigated by response surface methodology (RSM) under central composite design (CCD). Analysis of variance (ANOVA) exhibit a high R² value of 0.999 and confirm suitability of constructed second-order regression model for excellent evaluation and prediction of the experimental data. The interaction and main factor and optimum conditions of the under study process were determined from response surface plots based on desirability function. The maximum CR adsorption were achieved at pH of 4, 15 mg L^-1 of CR, 0.017 g of Au-Fe₃O₄-AC and 5 min sonication which owing to 99.49% removal efficiency is highly recommended for future CR removal from different matrixes. Adsorption kinetic follow second-order rate expression in combination to inter particle diffusion and equilibrium adsorption data best represented by the Langmuir isotherm with maximum mono-layer adsorption capacity of 43.88 mg g^-1.

The Role of Nanomaterials and Nanotechnologies in Wastewater Treatment: a Bibliometric Analysis

Nanomaterials and nanotechnologies (NNs) have been shaping the wastewater treatment process unprecedentedly. Bibliometric methods are regarded as an indispensable light to guide direction in scientific domain. The present study aims to investigate the role of NNs in wastewater treatment with bibliometric techniques based on SCI databases from 1997 to 2016. Results showed that China (962), USA (324) and Iran (140) are the most productive countries. Chinese Academy of Sciences (149), Tongji University (49), and Harbin Institute of Technology (40) from China are the most contributive institutions. China and USA played central roles in cross-national cooperation, but the top three Chinese institutions displayed limited vitality in overseas communication. Rsc Advances (108) was the most productive journal followed by Desalination (97) and Desalination and Water Treatment (96). The research direction of NNs in wastewater treatment was bound up with new NNs. Novel preparation methods and nanostructures were powerful impetus for its progress. Nanomaterials like graphene, nanotube, magnetic nanoparticle, and silver nanoparticle were hotpots in this field. Current and potential application of NNs in wastewater treatment as well as challenges were reviewed based on bibliometric results. This study also provided researchers future-minded advice about research topic selection.

Sonochemical incorporated of cytosine in Cu-H2bpdc as an antibacterial agent against standard and clinical strains of Proteus mirabilis with rsbA gene

The cytosine embedded copper based metal-organic framework (Bio-MOF) was synthesized by facile one-step sonochemical method by simply mixing of 4-4, biphenyldicarboxylic, cytosine and copper nitrate (Bio-Cu-H₂bpdc-Cy). The prepared bio-MOF was characterized by XRD, FTIR and FE-SEM techniques. The effect of Cu-H₂bpdc-Cy on the expression of the rsbA gene was evaluated in the clinical and standard Proteus mirabilis and study of MIC of Cu-H₂bpdc-Cy by microdilution against them that have the rsbA gene. According to different concentrations of MIC, MBC concentrations was cultured on blood agar culture medium. Regarding to the concentration of MIC, gene expression changes were obtained by real-time PCR. MIC for standard and clinical strains of Proteus mirabilis was 1.6 and 1.8 mg/ml, and also MBC was obtained to be 1.8 and 2.0 mg/ml, respectively. Finally, in the real time PCR method, expression of the rsbA gene in presences of bio-Cu-H₂bpdc-Cy was reduced, but has no effect on the gene expression of the Housekeeping DNA Gyrase-B gene. Considering the effect of Cu-H₂bpdc-Cy on the rsbA gene in Proteus mirabilis bacteria, it is possible to use of Cu-H₂bpdc-Cy agent as a therapeutic supplement against this bacterium.