مجله محیط زیست و مهندسی آب
سال یازدهم شماره 1 (بهار 1404)

The carcinogenicity and high toxicity of chromium (VI) show that the removal of this pollutant in industry, water resources, and the environment is necessary. Nanoporous materials have a high ability to remove pollutants. The aim of this study was to synthesize SBA-16 nanostructure using P123 and F127 surfactants and TEOS precursor and grafting its surface in two steps with -NH2 (NH2-SBA-16) and then with copper (Cu-NH2-SBA -16). Cu-NH2-SBA-16 was identified as a new adsorbent by XRD, SEM, EDX, and FT-IR analysis. The synthesis of nanoporous functionalized with amino group -NH2 was done by reflux and then grafting of prepared nanoporous with copper (II) solution was performed. The maximum adsorption capacity of NH2-SBA-16 and Cu-NH2-SBA-16 was 6.66 and 34.48 mg/g, respectively. In addition, the kinetics of chromium adsorption followed the pseudo-second-order kinetic model. The maximum efficiency of chromium removal by Cu-NH2-SBA-16 for contact time, initial concentration, amount of adsorbent, pH and temperature were 15 min, 10 mg/l, 1 g/l, 2, and 25 °C, respectively; adsorption capacity of Cu-NH2-SBA-16 increased after the modification process. The synthesized nanoadsorbent with an efficiency of 90% had a spontaneous and endothermic adsorption process, and its adsorption capacity did not decrease significantly after 3 regenerations.

This research aims to investigate the reduction of CO2 emissions in the cement production process by producing pozzolanic portland cement (PPC) with the characteristics of ordinary portland cement (OPC) using quality-improving chemical additives including calcium nitrate (CN), calcium formate (CF), triethanolamine (TEA) and triisopropanolamine (TIPA). To this end, CN and CF (1, 2 and 3% wt of binder) were added to PPC mortar during the making process, and TEA and TIPA (0.003, 0.006 and 0.01% wt of binder) were added as a solution to the mixture of clinker and natural pozzolan during grinding. The results obtained from compressive strength tests illustrated that, on average, PPC samples containing 15% natural pozzolan led to a 2.7% decrease and a 17.3% increase in the compressive strength respectively compared to OPC with 1% CF and 0.01% TEA. Accordingly, for cement production, clinker can be reduced by 15%, and natural pozzolan be replaced; the reduction in resistance caused by adding natural pozzolan can also be compensated by using chemical additives. Hence, the possibility of replacing 15% of natural pozzolan with clinker, while maintaining the quality of produced cement and reducing the emission of 135 kg of CO2 per ton of cement production is one of the results of this research.

This study aimed to improve the mechanical properties of soil and foundations through geopolymer synthesis. The soil used in this research was wind-blown sand exposed to erosion. To examine the mechanical properties of the soil, laboratory tests were conducted, including Atterberg limits, soil permeability coefficient, sand equivalent value, soil pH, optimum moisture content, unconfined compressive strength (UCS), and particle size distribution. The results indicated that the uniformity coefficient (Cu) and curvature coefficient (Cc) were 2.5 and 1.23, respectively, classifying the soil as poorly graded. Based on the soil’s silt and clay content, it was classified as sand. The particle size distribution test showed that 5% of the soil passed through the No. 200 sieve. Hence, the soil is coarse-grained and poorly graded. The soil density was determined to be 2.65 g/cm³, confirming that the soil is sandy and quartzitic, and due to its lack of cohesion, it exhibits zero compressive strength. The permeability coefficient was 1×10⁻³ cm/s, the sand equivalent value was 79%, and the soil pH was 7.7. The geopolymer sample with diatomite exhibited the highest strength.The key factor in the geopolymerization process is SiO₂, and with strength comparable to cement, it is a suitable alternative to reduce the environmental impact of cement production.

The selection of landfill sites and the utilization of modern sanitary burial methods must consider the environmental regulations of each country. Given the impacts that landfill sites have on ecosystems and their surrounding environments, it is essential to ensure that the location chosen for landfill minimizes destructive effects and adverse impacts on its surroundings. The objective of the present study was to identify suitable locations for the disposal of industrial waste in Mazandaran Province. Iran. In selecting waste disposal sites, all environmental, geological, hydrological, topographic, physiographic, climatic, soil science criteria, protected areas, buffer zones for oil, water and power transmission lines, access roads, population areas, and other criteria stipulated in legal regulations were considered. The spatial analysis of the results of this study showed that 22.6% of the area of Mazandaran Province conflicts with 15 environmental criteria. The results from overlaying the prepared informational layers, while adhering to each technical standard for establishing an industrial and special waste storage center using the Boolean method, indicated that none of the areas in Mazandaran Province meet the current technical standards for establishing a special waste storage center, and it is not feasible to establish such a center in Mazandaran Province.

Subsidence poses a significant management challenge, causing damage to infrastructure, energy transmission lines, buildings, soil stability, and leading to the formation of sinkholes. This study employed the Multilayer Perceptron (MLP) neural network to evaluate and model the extent of subsidence in the Dehgolan Plain aquifer, located in Kurdistan Province, Iran, between March 23, 2022, and September 24,2023. A subsidence model was constructed using groundwater level data, changes in transmissivity, alluvial thickness, and results from radar interferometry. Regression analysis comparing predicted and observed values confirmed the model's high accuracy in forecasting subsidence. Furthermore, the model successfully estimated missing subsidence rates. The maximum subsidence calculated using radar interferometry over the 552-day period was 154 mm, while the maximum uplift was 16 mm. In comparison, the MLP model estimated a maximum subsidence of 145 mm and a maximum uplift of 12 mm. Subsidence was found to be more pronounced in the western and central regions of the plain compared to the eastern areas. Considering the ongoing progression of subsidence in the Dehgolan Plain aquifer, it is imperative to implement strategies to reduce the over-extraction of groundwater and establish continuous monitoring systems.

Estimating the optimal water requirement requires determining the relationship between climatic conditions and evapotranspiration. As a result, water resource management relies on accurate estimation of evapotranspiration. This study aimed to monitor and predict the reference evapotranspiration, ET0, in the Moghan Plain, considering the impact of climate change. ET0 was calculated by the PMF56 method using CROPWAT software. The 30-year data (1993-2022) of the Parsabad synoptic station and the output of CMIP6, including the HadGEM3-GC31-LL model and the SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios were used. The results showed that the precipitation, minimum temperature and maximum temperature in the Moghan Plain from 261 mm, 9.95 °C and 21.21 °C in the base period, respectively, will reach 361 mm, 16.04 °C and 27.68 °C at the end of the century. Under the effects of climate change, ET0 will increase in the future. The severity of the climate change impact on ET0 in the Moghan Plain is greater in the warm months, and the greatest increase will be under the SSP5-8.5 scenario. The ET0 in Moghan Plain reached 1114 mm/yr in the base period, with an increase of 20% to 1334 mm/yr at the end of the century. Considering the greater share of Iran's water consumption in the agricultural sector, especially in areas such as the Moghan Plain, ET0 changes should be considered in engineering and water resource management programs.

Location identification for the construction of small water storage reservoirs is currently receiving significant attention, particularly in regions experiencing reduced precipitation, such as arid and semi-arid areas. This study utilized various Multi-Criteria Decision-Making (MCDM) techniques, including the Analytic Hierarchy Process (AHP), Analytic Network Process (ANP), and Boolean logic, to pinpoint the suitable areas for placing small water storage reservoirs (SWSRs). Criteria such as distance to water resources, water salinity, topography, land use, geological attributes, road accessibility, and climatic conditions were considered. The zoning maps of criteria were prepared, and after conducting pairwise comparisons and determining their weight coefficients, the final land classification map was produced. The findings revealed that access to water resources emerged as the most critical criterion. The location maps generated through the AHP and ANP methods showed that 50.2% and 51.7% of the total study area were deemed suitable, respectively, with 18.2% and 16% classified as unsuitable. In comparison, the Boolean method indicated that 5.6% of the area was suitable for constructing SWSRs, while 94.4% was unsuitable. Finally, AHP and ANP techniques are suggested for determining the appropriate locations for constructing SWSRs.

One of the desirable solutions to overcome environmental challenges is the education and training of academic-educated human resources holding an environmental perspective. Therefore, the aim of the present research was to model the relationship between concerns and environmental attitudes of students at the Agricultural Sciences and Natural Resources University of Khuzestan. The statistical population of this study included students enrolled and actively studying at this university during 2022-2023. The sample size of 161 was determined using the Cochran formula, and sampling was done using the proportional stratified-random manner. Findings indicated that 72% of the variance in students' environmental attitudes was predicted by environmental concerns. Moreover, environmental concern variables significantly modeled students' attitudes toward the environment. Therefore, to improve agricultural students’ attitude, influential figures such as pro-environmental academic members and other well-known individuals could hold seminars at universities discussing the importance of environmental conservation. and by delivering speeches at university seminars on promoting respect and environmental conservation. This could potentially shift students' perspectives on the environment, leading to an increased positive attitude towards environmental protection.