Carbon nanoparticles (CNPs) were produced from the leaves of Cocos nucifera and chemically activated using phosphoric acid. The activated CNPs were characterized using Brunauer-Emmett-Teller (BET) (surface area: 122.53 m2/g; mean pore diameter: 16.29 nm) and Field Emission Scanning Electron Microscopy (FE-SEM) (particle size: 20-30 nm). Batch adsorption experiments were conducted to optimize chromium (VI) removal from leather industry effluent. Response surface methodology with Central Composite Design (CCD) was employed to investigate the effects of four parameters: Cr concentration (10-100 ppm), CNP dosage (1-10 g/L), contact time (10-60 min), and pH (1-7). Under optimized conditions (Cr concentration 100 ppm, CNP dosage 10 g/L, contact time 30 min, and pH 2), the maximum removal efficiency achieved was 83% with an adsorption capacity of 83 mg/g. ANOVA analysis confirmed the quadratic model adequacy (F-value = 74.65, p < 0.0001, and R² = 0.9896). CNP concentration emerged as the most influential parameter. Isotherm modeling analysis demonstrated that the chromium biosorption process follows Langmuir isotherm behavior with an R² value of 0.9951, a Chi-squared error (χ²) value of 0.2452, and a root mean square error (RMSE) of 1.0002 mg/g, indicating monolayer adsorption. The Cocos nucifera carbon nanoparticles demonstrated high efficiency for chromium removal from tannery effluents under acidic conditions.
The toxic heavy metals in waste printed circuit boards (PCBs) in electrical and electronic devices make them particularly challenging to manage. This research emphasized the bioleaching and biosorption potential of two effective fungal strains for removing Cu²⁺, Pb²⁺, and Cd²⁺ from laptop PCBs. The bioleaching experiment demonstrated that the two-step bioleaching process using Aspergillus niger effectively extracted heavy metal ions from laptop PCBs. One kilogram of laptop PCB samples contained 130.25±1.53 g of Cu, 18.81±0.09 g of Pb, and 0.037±0.004 g of Cd. The results suggest that Cu2+, Pb2+, and Cd2+ achieved maximum bioleaching efficiencies of 73.06%, 63.91%, and 70.53%, respectively, after a 21-day incubation period. The biosorption experiment using immobilized Humicola phialophoroides biomass pretreated with NaOH demonstrated higher efficiency in removing heavy metal ions from leachate than non-immobilized biomass in bioremediation processes. The maximum heavy metal biosorption by the immobilized cells was achieved at a solution at 30 oC after an equilibrium time of 120 minutes at pH 7. The heavy metal ion biosorption capacities were 184.10±3.65 mg Cu g-1dry wt., 39.60±1.21 mg Pb g-1dry wt., and 2.28±0.04 mg Cd g-1 dry wt. The temperature had little effect, while the pH value significantly influenced the sorption process.
In the present research, a magnetic nanostructure based on graphene oxide and iron oxide modified by the amino acid tryptophan was synthesized. The properties of the adsorber were determined using a Fourier transform infrared spectrometer, elemental analysis, X-ray diffraction, a scanning electron microscope, and a vibrating-sample magnetometer. Optimum parameters such as pH, contact time, amount of used adsorbent, initial concentration of copper ions, and the effect of temperature were investigated. Adsorption isotherm studies were conducted using the Langmuir and the Freundlich models, and the Langmuir isotherm model was found to be more consistent with the adsorption process. The theoretical maximum adsorption capacity of the adsorbent was 125 mg of copper per gram of adsorbent, which was close to the maximum adsorption capacity of the adsorbent in the real state (118 mg of copper per gram of adsorbent). To investigate the thermodynamics of adsorption, the Van't Hoff Equations were used. The results indicated that the adsorption process was endothermic. In addition, the removal rate of copper ions from the real wastewater sample in the presence of other ions was determined to be 46%.
Due to increasing environmental concerns and requirements, the adoption of modern heating methods is strongly recommended. The microwave-based system has attracted considerable attention due to its efficiency, low carbon footprint, low energy consumption, and short process timing. Our studies on microwave heating for synthesizing cobalt and various alloys showed a significant need for novel predictors to model microwave heating processes. This paper is novel in its evaluation of the performance of outstanding numerical methods for solving microwave-based reactions in both kinetic and environmental aspects. As a case study, the experimental results related to the reaction of cobalt metal oxide with syngas under microwave heating were compared to the orthogonal collocation outcomes, and outstanding results were reported with a mean error lower than 5%. The emissions from a microwave and an electrical furnace, based on kinetic values, were also compared. To evaluate numerical methods for different types of reactions in the mentioned microwave heating process, the governing equations from the modeling of gas-solid catalyzed reactions with different reaction orders were solved using the perturbation and orthogonal collocation methods. The environmental analysis demonstrated that the microwave process offered notable environmental and operational advantages over the furnace process, including significantly faster CO removal, more controllable CO₂ emissions, higher energy efficiency, and a reduced overall carbon footprint by possibly reducing energy consumption.
The pervasive presence of nanoplastics and antibiotics in wastewater systems presents a dual threat to environmental and public health. Nanoplastics, with particle sizes under 1 μm, have become a major environmental contaminant, primarily due to their durability and potential to absorb harmful chemicals. These particles not only threaten aquatic ecosystems by disrupting microbial communities and harming marine life but also pose risks to human health through bioaccumulation in the food chain. Similarly, antibiotics frequently found in wastewater promote the development of antibiotic-resistant bacteria, further endangering ecological stability and human health. The synergistic effects of nanoplastics and antibiotics exacerbate their impacts, particularly by increasing the bioavailability and toxicity of contaminants in aquatic systems. This paper explores the sources, transport pathways, and combined ecological and health impacts of these pollutants. Additionally, it discusses the limitations of current wastewater treatment technologies in mitigating the effects of nanoplastics and antibiotics and proposes advanced strategies for reducing their environmental footprint. Addressing these contaminants requires a multifaceted approach, integrating technological, regulatory, and community-based solutions to safeguard the ecosystem, biodiversity, and human health.
The capacity of adsorbent materials to simultaneously treat multiple pollutants plays a crucial role in determining the efficiency of practical water and wastewater treatment. Triamine-functionalized activated rice husk ash (TRI-ARHA) was successfully synthesized and exhibited considerable potential as a simultaneous adsorbent for organic compounds, nitrate, and phosphate. This study investigated the effects of the HF concentration in the process of activating rice husk ash as a support, the ratio of triamine silane to activated rice husk ash, and the type of amine functional group used in the grafting process on the synthesis of the TRI-ARHA material; these synthesis conditions were optimized using an experimental design approach. The results showed that the maximum adsorption capacities of TRI-ARHA material for MO, nitrate, and phosphate were approximately 15.8 mgMO/g, 34.3 mgNO3--N/g, and 13.4 mgPO43--P/g, respectively, under the optimal synthesis conditions with an HF concentration of ~ 4.86% and triamine silane to an activated rice husk ash volume ratio of ~ 3.12 mL/g. Validation of the optimized TRI-ARHA material demonstrated practical adsorption performance, achieving approximately 93.1% of the model's predicted performance. Overall, a basic TRI-ARHA synthesis procedure has been established to support further research, development, and practical applications. This contributes to improved water and wastewater treatment efficiency, promoting the circular economy of rice husk ash waste.
This study explores the photocatalytic degradation of Rhodamine B (RhB) under sunlight irradiation using Cu2Cr-LDH/BiOCl and Cu2Cr-LDH/TiO2 nanocomposites. The structural, optical, and morphological properties of the materials were thoroughly examined by X-ray diffraction (XRD), Ultraviolet–visible spectroscopy (UV-vis), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The primary objective was to assess the photocatalytic efficiency of these nanocomposites in degrading RhB dye under sunlight. The Cu2Cr-LDH/BiOCl nanocomposite exhibited superior photocatalytic performance, achieving 90.29 % RhB degradation, significantly outperforming Cu2Cr-LDH/TiO2 (56.45%) and pure Cu2Cr-LDH (31.36%). This enhanced efficiency is attributed to the formation of a heterojunction between Cu2Cr-LDH and BiOCl, which facilitates effective separation and transfer of charge carriers. The improved photocatalytic activity is primarily attributed to the well-dispersed BiOCl phase on the Cu₂Cr-LDH surface, demonstrating that interfacial architecture plays a more critical role than simply increasing the Bi or Ti content. Hydroxyl radicals and holes were determined to be the primary active species responsible for the degradation process. Additionally, both nanocomposites demonstrated remarkable stability and reusability, retaining high catalytic efficiency over four consecutive cycles. A detailed photocatalytic mechanism was proposed to explain the enhanced activity of the nanocomposites, highlighting the synergistic effects of the heterojunction structure and efficient charge carrier dynamics.
In recent years, the use of water quality indices (WQI) to ensure the safety of drinking water has expanded. In this study, the quality of drinking water in Shahrekord was investigated. This study involves measuring eight physicochemical parameters (pH, EC, TDS, TH, SO42-, PO43-, NO3-, Turbidity) of drinking water taken from the urban water network and calculating the water quality index. The obtained water quality index obtained for all water samples was below 50, indicating excellent and very good quality of Shahrekord's drinking water. After applying principal component analysis, the results indicated that first component, with the highest eigenvalue, is influenced by parameters such as sulfate, nitrate, electrical conductivity (EC), and TDS, confirming the salinity and chemical water quality are dominant. The second component, driven by phosphate, total hardness (TH), and turbidity, reflects the physical properties and hardness of water. The third component is associated with the contribution of phosphate and hardness. EC and TDS exhibit a high correlation.
Nowadays, immobilized photocatalyst clay beads have attracted considerable research interest due to their outstanding properties, including enhanced stability, easy recovery and reuse, and reduced secondary pollution. In this study, novel titanium dioxide/zinc oxide composites were synthesized via the sol–gel method and immobilized on clay beads using the dip-coating process. Various titanium dioxide/zinc oxide ratios were used to obtain different composites. For the immobilization procedure, four titanium dioxide/zinc oxide layers were coated on clay beads, dried in the oven at 100°C for 30 min, and subsequently calcined at 2°C/min up to 500°C. The coated beads were characterized using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). Photocatalytic degradation experiments were conducted to test their performance using methylene blue as a model pollutant. The highest methylene blue degradation efficiency was achieved with pure titanium dioxide-coated clay beads. All titanium dioxide/zinc oxide composites maintained their photocatalytic performance after five consecutive recyclability experiments. This work aims to demonstrate a reproducible, scalable, and economic immobilization procedure for single and composite photocatalysts on clay beads with outstanding photocatalytic performances for wastewater treatment.
In recent years, bioremediation has attracted a great deal of attention because of environmental pollutants and their implications for public health and environmental sustainability. In bioremediation, microalgae play a major role in environmental and wastewater treatment techniques. Among environmental contaminants, heavy metals (HMs) are significant pollutants due to their persistence in the environment and their potential to harm ecosystems and human health. Several conventional techniques are available for removing heavy metals, but they are expensive. Microalgae afford an environmentally friendly approach for heavy metal remediation. This review examines the major sources and health effects of heavy metals, including chromium (Cr), arsenic (As), zinc (Zn), cadmium (Cd), Iron (Fe), mercury (Hg), lead (Pb), and Copper (Cu), emphasizing microalgae as a potent tool for heavy metal decontamination. The primary analyses observed microalgal metallothioneins (MTs) and their potential to improve metal sequestration, supported by computational investigations of metal-MT interactions. The study revealed that metal ions with MT proteins binding energies of MT ranged between -16.67 to –3.24 kcal/mol for P. tenue and –5.90 to –3.21 kcal/mol for C. sorokiniana, –2.86 to –1.41 kcal/mol for S. platensis, indicating variable but significant affinity for different metal ions. These results suggest that microalgal MTs play an important role in heavy metal uptake and can be further enhanced using computational and biotechnological techniques. Based on the evidence reviewed, microalgae-based bioremediation systems with MT-enhanced strains are recommended as a potential and long-term solution for heavy-metal removal.
The expansion of urbanization, industrialization, and population has led to water pollution due to severe contamination by toxic pollutants, increasing the demand for pure water. Arsenic poisoning of water is considered a highly hazardous chemical poisoning due to its harmful effects on the environment and human health. The present study combines nanotechnology and membrane technology to overcome water scarcity issues and the removal of arsenic from contaminated water. Polyethersulfone (PES) hollow fiber membranes, with and without nanoparticles (NPs), were fabricated through the dry-wet spinning process and used for ultrafiltration studies. Physicochemical characterization confirmed the successful synthesis of bare nanoparticles, and further, membranes were characterized and analyzed by various studies. The study demonstrated significant improvements in As (V) removal efficiency and water flux. The optimized membrane achieved a removal rate of 79.23% and the highest flux of 26.7 L/m²/h compared to the pristine membrane, which had a 65% removal rate and a flux of 18 L/m²/h, emphasizing potential for water purification applications.
Industrial effluents have emerged as a critical environmental challenge due to limited water resources, their toxic nature, and carcinogenic properties. Therefore, it is essential to treat industrial wastewater and eliminate toxic pollutants. This study focuses on synthesizing nanocrystals of zeolite imidazole frameworks (ZIF-8) by doping with iron to create a porous ZnFe/ZIF-8 (ZFZ) composite using a green method (water solvent) to enhance performance and synergistic effects. The morphology of ZFZ nanocrystals was analyzed using a variety of complementary characterization techniques (Fourier Transform Infrared (FTIR), X-ray diffraction (XRD), and scanning electron microscope (SEM)). The ZFZ and ZIF-8 were assessed for the removal of Direct Red 23 (DR-23) dye from wastewater by varying the effective variables (pH, dye dosage, initial concentration, an(d contact time). For comparative analysis, ZIF-8 was also synthesized and used in conjunction with ZFZ to remove the DR-23 dye. The results demonstrated that ZFZ possesses a significantly higher adsorption capacity (383 mg/g) for DR-23 than ZIF-8 (94.79 mg/g), representing a fourfold enhancement. At a contact time of 120 minutes, the ZFZ composite achieved a maximum removal efficiency of 92.3% with 0.006 g of adsorbent at pH 3. Analysis of the equilibrium adsorption data for anionic dyes confirmed a strong alignment with the Langmuir model (R² = 0.99), consistent with a homogeneous, monolayer adsorption process. Additionally, the adsorption mechanism on ZFZ and ZIF-8 composites followed second-order kinetics with R² = 0.99. These findings confirm that synthesized ZFZ is an efficient adsorbent for the remediation of dye-contaminated wastewater.
This research explores the production of spherical activated carbon derived from glucose using the combination of a hydrothermal process followed by chemical impregnation with hydrogen peroxide (H2O2), citric acid (CA), and acrylic acid (AA), and pyrolysis. The adsorption performances, kinetics, and thermodynamics of the synthesized materials were compared with those of the material without chemical impregnation using batch experiments. Boehm titration and Fourier-transform infrared spectroscopy (FTIR) confirmed an increase in oxygen-containing functional groups (carboxyl, lactone, and phenol), facilitating adsorption through electrostatic interaction, reduction, and complexation. Adsorption kinetics and isotherm modeling confirmed that the process adhered to the Elovich model and the Redlich-Peterson or Langmuir isotherm, suggesting chemisorption dominance. Among the materials tested, AA-modified activated carbon (AC-AA) exhibited the highest adsorption capacity of 244 mg/g, outperforming previously studied biochar-based adsorbents. Kinetic and thermodynamic assessments demonstrated that Cr(VI) adsorption was spontaneous (ΔG<0), endothermic (ΔH>0), and entropy-favored (ΔS>0). Notably, the study elucidates the concurrent adsorption and reduction of Cr(VI) to Cr(III) at low pH, driven by electron transfer from surface functional groups. Moreover, NaOH was identified as the most effective desorption agent, underscoring the potential for material regeneration and reuse. This research highlights the potential application of glucose-based carbon spheres with functionalized surfaces as a sustainable, cost-effective solution for Cr(VI) removal in industrial wastewater treatment.
The treatment of high-strength wastewater generated from fermented rice noodle production poses significant environmental challenges due to its elevated organic load, acidity, and nitrogen content. This study investigated the optimization of wastewater treatment using Effective Microorganisms (EM), focusing on the effects of initial wastewater pH (6–8) and EM dosage (1–10% v/v) on Chemical Oxygen Demand (COD) and Total Kjeldahl Nitrogen (TKN) removal efficiency. A Central Composite Design (CCD) within the framework of Response Surface Methodology (RSM) was employed to model and analyze the interactive effects of these operating parameters. The results demonstrated that near-neutral pH (6.9) and a low EM dosage (1.2% v/v) yielded the highest COD removal efficiency (80.21%), whereas an alkaline pH (8.0) with a low EM dosage (1% v/v) resulted in the maximum TKN removal efficiency (75.18%). Statistical analysis revealed that EM dosage significantly impacted COD removal (p < 0.0001), while initial pH had a more pronounced effect on TKN removal (p < 0.0001). The quadratic regression model exhibited strong predictive performance for both COD (R² = 0.9827) and TKN (R² = 0.9326) removal. The findings further indicate that COD removal is predominantly governed by biologically regulated microbial metabolism, whereas TKN removal is controlled mainly by pH-driven physicochemical pathways. Overall, the EM application optimized through RSM represents a promising and sustainable strategy for enhancing the simultaneous removal of organic matter and nitrogen from wastewater generated by the fermented rice noodle industry.
This study investigated the complex relationships among environmental factors in coastal settings and identified potential sources of microplastics in tropical coastal and river sediments within a non-industrial urban area. The research was conducted along the northern coast of Aceh, Indonesia, encompassing two river estuaries: the Krueng Aceh and Krueng Lamnyong. The results indicate that land use, population density, and distance from the river estuary influence the distribution of microplastics in coastal sediments. The Krueng Aceh River, which is associated with a higher population density, exhibited greater levels of microplastic contamination than the Krueng Lamnyong River. The formation of estuarine turbidity maxima (ETM) is considered a key factor controlling microplastic distribution along the Krueng Aceh River, whereas distribution patterns in the Krueng Lamnyong River appear to be more strongly influenced by local anthropogenic activities and environmental conditions. The study area is distinctive because, despite the absence of major industrial sources, identifying microplastic origins remains complex. In coastal zones, tourist sites tend to exhibit lower microplastic abundances, likely due to stricter waste management practices, whereas non-tourist areas show higher levels of contamination. This study provides new insights into the distribution and potential sources of microplastics in tropical non-industrial urban environments and offers a foundation for developing more effective mitigation strategies for microplastic pollution.
Restaurant waste is a potential biomass to be developed into a renewable energy, especially in biogas production. It is the main substrate for anaerobic process, as it contains many organic materials. Tofu liquid waste and cow dung have the potential to be used as an additional substrate in this process. This research aims to determine the effect of variations in the restaurant waste, tofu liquid, and cow dung composition towards the quality of methane gas in biogas production. It was conducted using a 30 liters reactor with a working volume of 22.5 liters. The substrate variables included 50%, 93.75%, and 100% variations of restaurant waste, 50% tofu liquid, and 6.25% cow dung. The results showed that the variations in the organic waste composition affected methane gas quality in biogas production. The reactor with 100% restaurant waste substrate, obtained the highest yield in each parameter. The anaerobic treatment with 100% restaurant waste substrate in reactor C yielded the highest values for each parameter. Additionally, the largest volume of biogas formed in this reactor was 109 liters, with a methane gas concentration of 51.307 ppm which is followed by reactor B and then reactor A with biogas production of 48 Liters and 45 Liters. The ratio of methane and carbon dioxide levels in the biogas formed was 60% and 40%.
Water contamination is a significant environmental issue, and it is crucial to develop innovative technologies to address this problem. One such technology is the use of nanomaterials in polymeric membranes, which can help to purify water by eliminating pollutants and heavy metals. These membranes possess exceptional properties, including a large surface area, adjustable pore dimensions, and permeability selectivity, which make them effective in removing various contaminants from water. Nanoscale materials, like metal nanoparticles, nanofibers, graphene, and graphene oxide, and metal organic framework (MOF), are integrated into the membrane, which enhances its mechanical strength, separation efficacy, and adsorption capabilities. In the current investigation, we have successfully synthesized the metal-organic framework NH2-MIL-125 and conducted preliminary research on its properties for heavy metal rejection (Pb2+ and Cd2+) after incorporation into a polysulfone membrane. Field Emission Scanning Electron Microscopy (FESEM), X-ray Diffraction (XRD), Brunauer–Emmett–Teller (BET) analysis, an Electrokinetic Analyzer, and Fourier Transform Infrared Spectroscopy (FTIR) were used to study the membranes. Additionally, the membrane's water affinity, flow rate, and resistance to fouling were studied. The M-3 membrane with 3.0 % MOF incorporation showed a 99.10 % rejection for cadmium, and the M-3 membrane rejected 75.02% for lead at a feed concentration of 500 ppm.
In this research, the dispersion of gaseous pollutants emitted from the Sahand thermal power plant was simulated using AERMOD software to determine the concentrations of sulfur dioxide, nitrogen dioxide, and carbon monoxide in the surrounding area. AERMOD was used to analyze the concentration patterns of these pollutants within a 35.9 km2 domain, covering the cities of Bonab, Ajabshir, and Khoshehmehr, along with their nearby villages. For this purpose, two years of meteorological data, along with geographical information and emission source characteristics, were utilized to estimate pollutant concentrations over averaging periods of 1 hour, 3 hours, 24 hours, and annual averages. Comparison of the modeled results with the limits defined in the environmental standards indicates that the maximum concentrations of nitrogen oxide and carbon monoxide in residential areas are within the permissible limits. However, the highest concentration of sulfur dioxide exceeds the limits in some villages, suggesting a potential health risk for residents.
This study evaluates the synergistic integration of phytoremediation using Pistia stratiotes (Kayu Apu) and microbial bioaugmentation with Effective Microorganisms 4 (EM4) for treating landfill leachate. A batch system was employed with EM4 concentrations of 0%, 10%, 20%, and 30% and residence times of 3, 6, and 9 days. The results indicate that the highest pollutant removal efficiency was achieved with 30% EM4 and a 9-day residence time, resulting in 41.5% BOD reduction, 37.3% COD reduction, and 38% TSS reduction. Additionally, DO levels increased significantly by 488.24%, indicating improved aerobic conditions, which are essential for microbial activity. These findings demonstrate the potential of integrating Pistia stratiotes and EM4 as a sustainable, eco-friendly approach to treating landfill leachate. Further research is recommended to optimize operational parameters, scale up the system, and ensure compliance with regulatory discharge standards.
Membrane science is gaining importance in the emerging field due to its fewer energy consumption and low maintenance. Many surveys and studies were concentrating on specific membranes for specific applications. Trial-and-error approaches in membrane design result in inefficiencies, including time and material wastage. There is a need for developing a generalized model with minimal parameters and resulting membrane satisfying separation applications. Enhancement of membrane performance is crucial and hence many researchers considered the fabrication and design aspects of membrane parameters as research criteria for different applications. High surface area, ease of maintenance, and low cost make them attractive to different applications including the bio-medical sector, food and beverages, water filtration, gaseous environment, etc. However, membrane design and configuration demand several experiments specific to the applications. Hence it is still considered to be a challenging process thus opening new avenues towards automating the process. This review comprises a summary of state-of-the-art membrane technology and its application in the separation phenomenon providing a machine learning perspective in membrane science and engineering.
