International Journal of Environmental Science and Technology最新文献

To generate sustainable products, composite industries must use readily available natural resources and agricultural waste as raw materials. The current study is focused with the separation and characterization of Chromolaena Odorata stem fibers from the stem of the often-encountered wild plant C. Odorata, which remains as agricultural waste after its life cycle, causing an unpleasant odour in the environment. Comparisons of C. Odorata stem fiber to other commonly used natural fibers were conducted to ensure C. Odorata stem fiber’s potential and viability in improving the sustainability of the automotive sector, pointing to an effective waste management approach. According to estimates, C. Odorata stem fiber has a primary cellulose content of 67.45 wt%, less wax of 0.96 wt%, a lower density of 1.11 g/cm³, an elevated crystallinity index of 51%, tensile strength ranging from 129 to 208 MPa, and Young’s modulus ranging from 2.7 to 4.0 GPa. Furthermore, thermal study (Thermogravimetric and Digital scanning calorimetry) ensures the thermal stability of C. Odorata stem fiber up to 232 °C, as well as exothermic and endothermic behaviors at such temperatures. Functional groups in C. Odorata stem fiber were found using Fourier transform infrared spectroscopy. The evaluation of C. Odorata stem fiber values and surface texture using scanning electron microscopy and atomic force microscopy supports the use of environmentally friendly C. Odorata stem fiber as an augmentation material in polymer composites for light-weight structural applications.

With the spread of environmental pollution, environmental recovery has turned into a critical goal of governments. Energy efficiency and the use of renewable energy are two essential solutions to control the emission of greenhouse gases. However, the research on these effective tools in reducing greenhouse gas emissions at macro and systemic levels in the power sector is insufficient. The present research uses the comprehensive approach of system dynamics to investigate these policies for reducing CO₂ emissions in Iran’s electricity generation sector. The results show that both policies are effective in improving the country’s energy security, but the impact of the renewable development policy in reducing carbon emissions is more prominent. Furthermore, the results showed that by implementing the photovoltaic development policy, access to the 21% share of this sector of the entire Iranian electricity sector can be realized by the end of 2033. Also, improving the efficiency of thermal power plants by up to about 3.5% can be achieved by implementing the policy of increasing efficiency.

The purpose of this study is to compare the life cycle assessment and reliability of different rainwater harvesting (RWH) systems in residential buildings in Tehran for a period of 50 years. Four main scenarios based on the number of stories (1, 2, 3, and 4) each including five sub-scenarios based on the size of the rainwater storage tank (2.5m³, 5m³, 7.5m³, 10m³, 12.5m³) and one using solely tap water were defined. Simapro software was used for life cycle assessment which was carried out using the endpoint and midpoint methods. The collected rainwater is assumed to be merely used to fill flush tanks and if it cannot satisfy this demand, tap water will be used. The results show that in an arid city like Tehran, collecting rainwater does not even come close to meeting non-potable water needs, and in most scenarios, tap water must be used for more than half of the days. Despite the low reliability of RWH systems, they perform better than tap water in most environmental impact categories because the processes used to produce tap water have the highest contribution to environmental damage. Among the sub-scenarios that use rainwater for flush tank demands, in almost all environmental impact categories, sub-scenarios that collect more rainwater (higher storage tank sizes) have better performance. The performance of sub-scenarios that use more rainwater is better in the endpoint environmental categories of ecosystems and human health; however, this trend is the opposite in the impact category of resources.

Graphical abstract

Low-cost nanocomposites composed of magnetite, and kaolin clay with two-dimensional graphene oxide (Fe₃O₄@GO@Ka) were fabricated with different ratios of graphene oxide (GO@Ka_1(2:1), GO@Ka_2(4:1), GO@Ka_3(8:1)) by cheap, and simple approach for oil droplets adsorption. FT-IR, XRD, SEM, HR-TEM, VSM, and BET were utilized to characterize Fe₃O₄@GO@Ka morphology and structure. The outcomes of characterization demonstrated that the graphene oxide had been prepared successfully on the kaolin surface. The influence of contact time, composite amount, oil droplets concentration, temperature, and pH of emulsion on the adsorption process was tested. The adsorption outcomes demonstrated that, in each experiment condition, an increase in the graphene oxide ratio on kaolin could efficaciously improve the elimination of oil droplets from the emulsion solution. Oil removal efficiency of 99.99% was achieved by Fe₃O₄@GO@Ka₃, higher than bare kaolin (25.3%). Optimum conditions were contact time 60 min, adsorbent dose 5 mg, initial oil 25 mg/L, temperature 308K and pH 7. Pseudo-second order kinetic model fitted the data best with chemisorption mechanism. Thermodynamic parameters were ΔH° = 187.5 kJ/mol, ΔS° = 0.6600 kJ/mol K, ΔG° = − 15.81 kJ/mol at 308K, confirming endothermic and spontaneous process. Maximum monolayer adsorption capacity from Langmuir model was 1428 mg/g. XRD validated structural stability after 4 cycles of reuse. An excellent regeneration performance of Fe₃O₄@GO@Ka₃ was observed via an ethanol-washing technique. These findings show the great potential of the Fe₃O₄@GO@Ka₃ nanocomposite as an adsorbent for the removal of oil droplets from oil-in-water emulsions.

Cooperation among companies is essential for reducing the whole-process carbon emissions of products, but the existence of asymmetric information can negatively affect the cooperation. The information-sharing framework based on blockchain technology can solve the problem and contribute to an efficient supply chain for collaborative carbon emission reduction. We obtain conditions on the optimal carbon reduction efforts of the producer and the retailer by designing a blockchain information sharing mechanism, and confirm that the optimal carbon reduction efforts are associated with consumers' low-carbon preferences. Our study shows that: (1) The blockchain-based information-sharing mechanism can improve the way that producers and retailers collaborate on carbon emission reductions and help them understand information on consumers’ low-carbon preferences to make scientific decisions. (2) Companies have to pay an information rent to ensure that consumers correctly disclose their low-carbon preferences under information asymmetry. Blockchain technology eliminates the information rent and enables the overall efficiency of the supply chain. (3) An optimal blockchain cost-sharing factor exists that maximizes the overall supply chain revenue under the mechanism.

This paper emphasizes the need for the stripping of the volatile organic compounds (VOCs) released from various sources owing to their deleterious effects on health and the environment. Granular activated carbon was applied as an adsorbent to adsorb VOCs such as toluene and xylene. This study investigated the influence of the operating variables such as length of the packed bed (0.015–0.025 m), VOC concentration in the inlet gas (2500–7500 ppm), and volumetric flow rate of gas (35–105 mL min⁻¹) on the performance of the adsorption column. Adsorption capacities as high as 6.2 kg kg⁻¹ and 9.054 kg kg⁻¹ were observed for toluene and xylene, respectively, at the VOC inlet concentration of 7500 ppm. Taguchi methodology was then used for the design of experiments by utilizing an L₉ orthogonal array with an objective to get a longer breakthrough time and maximum utilization of the adsorbent till the breakthrough. The breakthrough times obtained were 10.9 h (toluene) and 18.04 h (xylene). The maximum adsorbent usage till breakthrough (in %) was estimated to be 73.24 (toluene) and 84.36 (xylene). Subsequently, the grey relational analysis technique yielded the optimal parameters (length of the packed bed = 0.025 m, VOC concentration in the inlet gas = 5000 ppm, and volumetric flow rate of gas = 35 mL min⁻¹) when both the responses were optimized simultaneously. Gas flow rate was found to be the most sensitive parameter.

Graphical Abstract

Arsenic pollution has emerged through anthropogenic activities and natural mineral leaching processes. This study aims to advance the use of magnetic carbon nanocomposites (MCNs) in the sorption of arsenic, studying the influence of feedstock and the presence of carbon coating on magnetic nanoparticles. Previous works have shown that post-pyrolysis treatment improves the stability of MCNs by reducing iron leaching due to the formation of a carbon coating that encapsulates the iron oxide nanoparticles. However, this carbon coating could influence the adsorption properties of MCNs. This investigation deals with arsenic adsorption by four MCNs prepared by co-precipitation of magnetite (Fe₃O₄) nanoparticle into four carbonaceous matrixes, followed by a post-pyrolysis treatment. The pristine carbonaceous matrixes used in the present work were commercial activated carbon (CAC), charcoal (CC), hydrochar from the orange residue (HC_OR), and biochar from sunflower husk (BC_SFH). Pristine carbonaceous materials and MCNs without post-pyrolyzed were also used as arsenic sorbents in water solutions. Additionally, kinetic studies were carried out to explore the sorption properties of different MCNs and pristine materials, concerning the removal efficiencies (expressed as a percentage) and adsorption capacities, determining the equilibrium time. The results demonstrated that the presence of magnetite increases the adsorption of arsenic, being higher in the case of materials obtained by direct co-precipitation than in materials subjected to a post-pyrolysis process. The presence of a carbon layerprotecting the magnetite slightly decreases the adsorption of arsenic.

Nowadays, droughts and the impacts of climate change on water resources and the environment have had significant negative effects. Investigating the effects of climate change on drought indices and streamflow is crucial for water and environmental resource management. Therefore, the present study was conducted in two parts to examine the impact of climate change on drought indices and the amount of watershed streamflow. In the first part of this study, drought modeling was performed using the Standardized Precipitation Index (SPI) and emission scenarios (RCP4.5 and RCP8.5) at three temporal scales (3, 6, and 12 months) during the period of 1995–2055. Then, the climatic impacts on SPI for the period 2030–2055 under different climate scenarios were evaluated. The Karun basin in south west Iran, which is affected by droughts and the impacts of climate change, was selected as the study area. In the second part, the Adaptive Neuro-Fuzzy Inference System (ANFIS) was utilized to estimate watershed streamflow for a 20-year period. Subsequently, in this section, the Whale Optimization Algorithm (WOA) was employed to improve the results of ANFIS. Finally, streamflow prediction for the future period (2035–2055) was carried out using the hybrid model. The results indicated that analyzing precipitation through SPI under different climate scenarios could influence severe fluctuations in droughts within the study area. Frequency analysis of droughts under climate scenarios, RCP4.5 and RCP8.5, demonstrated an upward trend with diverse spatial prevalence patterns. On the other hand, the duration of droughts increased towards the RCP4.5 scenario and remained unchanged according to the RCP8.5 climate scenario. The northeastern, eastern, and southeastern regions will experience the longest and most frequent droughts compared to current conditions. Furthermore, the results of the second part showed that the developed ANFIS-WOA model provides better results (RMSE = 127, MAPE = 98.50, NSE = 0.73) compared to the ANFIS-based model with evaluation criteria of RMSE = 127, MAPE = 98.50, NSE = 0.73. Additionally, in the investigation of the impact of climate change on streamflow using ANFIS-WOA in the time range of 2030 to 2055, the flow rate in most months of the year will decrease by approximately 20 units compared to the baseline period, with a greater intensity of reduction in the RCP8.5 scenario than RCP4.5. However, there will be an increase in streamflow by approximately 20 (m³/s) only in October. The approach used in this study demonstrates the effects of climate change on the level of drought and watershed streamflow, serving as a warning for decision-makers and managers to better manage available water resources. Finally, this approach is recommended for implementation in other similar regions for water resource management and water supply assessment.

In this study, Aspergillus terreus was isolated from liquid radioactive waste and used as a dead biosorbent material to separate Y(III) from a solution containing both Sr(II) and Y(III). Fourier transform infrared spectroscopy, energy dispersive X-ray analysis, scanning electron microscope, and thermogravimetric analysis were also used to characterize the produced biosorbent fungus. A batch technique was conducted to study the biosorption behavior of A. terreus toward Sr(II) and Y(III) ions. The distribution behavior of Sr(II) and Y(III) as a function of pH in the range 1–5 has been studied. Y(III) from Sr(II) can be separated at all the pH ranges examined. The biosorption process was performed at different adsorption parameters such as pH, biosorbent weight, agitation time, and initial adsorbate concentration to get maximum removal of Sr(II) and Y(III) ions. After 30 min, both ions have reached equilibrium. The uptake percentage of Sr(II) and Y(III) increased with increasing pH value with a removal percentage of 9.5 and 99.5%, respectively, and was achieved at pH 5.00. The thermodynamic analyses revealed that the biosorption process was endothermic, spontaneous, and regulated mainly by physical biosorption. Nitric acid is the best desorbing agent among different eluting agents used. 0.1 M from HNO₃ is sufficient to eliminate about 76.65 and 81.10% of Sr(II) and Y(III), respectively, where A. terreus may be regenerated for reuse efficiently. The separation of Y(III) from a solution including Sr(II) has been established by a column technique with a breakthrough capacity of 1.43 mg/g for Sr(II) and 63.00 mg/g for Y(III). The results indicate that the A. terreus biosorbent is highly efficient in separating Y(III) from Sr(II).