Iranica Journal of Energy & Environment
Volume:12 Issue: 1, Winter 2021

The significance of toxic metals pollution treatment has become incrementally manifested as an important environmental issues in the recent years due to the urgent need to access healthy water and increase of the anthropogenic activities in water contamination. For efficient treatment of water contaminants, the selective and novel materials are always welcomed. In this study, the hydrothermally synthesized titanate nanotubes (TNT) were modified by the mercaptosilane modifier for the removal of Cu(II) and Ni(II) toxic contaminants. The modified TNT adsorbent (TNT/Sil) was characterized in terms of the physicochemical aspects and then, the experiments for capturing metal cations were performed in batch mode. The modified adsorbent presented more affinity for the removal of Cu(II) than Ni(II).Theresults demonstrated thatthe experimental data were highly fitted to the Freundlich isotherm model and the maximum uptake capacities for Cu(II) and Ni(II) were found to be 53.77 and 45.29 mg g-1, respectively. In addition, endothermic nature of the adsorption process was predicted by the thermodynamic study as well as the pseudo-second order model that was corresponded to the kinetic data. Considering these achievements and due to the surface hydroxyl and thiol functional groups, TNT/Sil adsorbent could be effective and promising material in the purification of wastewaters, contaminated with toxic metal cations.

To better homogenize the mixture of fuel and air in the combustion chamber and to enhance the controllability of ignition timing in Reactivity Controlled Compression Ignition (RCCI) engines, controlling the start of injection (SOI) timing can be essential. By changing the SOI timing, at some specific crank angles (CAs), the fuel can impact the edge of the piston bowl and create some difficulties. In this research, initially, efforts are made to recognize the range of SOI timing in which this collision process takes place (in the range of 44-54° bTDC), then, performance and the emission levels of the engine were evaluated in the beginning and end of this interval. The findings suggest that the nitrogen oxides emissions and the maximum in-cylinder mean pressure are higher in SOI of 44° bTDC, as compared to those in the SOI timing of 54°bTDC, although the latter has higher ignition delay and unburnt hydrocarbon (UHC) emission. Moreover, some evaluations were carried out to examine how the temperature of the fuel-air mixture can affect the performance of the engine in this specific range. It was found that as the IVC temperature increases, it rises the indicated mean effective pressure (IMEP), in-cylinder pressure, and NOx emission.

Chlorella vulgaris is one of the most common and characterized algae genus with several applications, including carbon sequestration, biofuel, food production and wastewater treatment. Chlorella sp. are considered suitable to be used as model organisms in space research due to their cultivation flexibility. Many studies have been carried out to ensure better conditions for supporting human life on long-term missions in deep space or on planetary surfaces, minimizing the need for resupplies. Regardless of the resilience of the genus Chlorella to space conditions has already been demonstrated, model organisms are useful in the improvement of new technologies. This research aimed to develop the culture conditions and a monitoring system for C. vulgaris, under microgravity, using an image capture device for CubeSats. The image acquisition system consisted of a digital microscope, with remote access, a Single Board Computer, a monitoring computer, and an image processing algorithm. Three microalgae colonies, under laboratory conditions, were evaluated in real time (every 30 minutes) using the size of the colonies as a parameter for evaluating growth rates. The highest microalgae biomass production for the three monitored colonies (C1-C3) was: increase of 28% for C1 after 90 h; 21% for C2 after 84 h; and 36% for C3 after 120 h. The results indicated that the system was able to monitor the growth of microalgae colonies. A specific support is being developed, which allows the installation of this image acquisition system for algae cultivation in a CubeSat, for future studies of algae growth in real microgravity conditions.

Small Diesel engines pose a very tough challenge of simultaneously meeting NOx and particulate matter (PM) emissions, without hampering performance and fuel consumption. Frequent revision in small diesel engines pose a very tough challenge of simultaneously meeting NOx and PM emissions, without hampering performance and fuel consumption. Frequent revision in emission norms for small diesel engines makes it further difficult, as they need to be upgraded in design and for combustion. These small, low-capacity engines are predominantly used in specific regions/countries where cost plays a major role and hence these engines lack a clear emission reduction strategy. It is required to develop an emission reduction strategy considering available technologies and cost implications. Current research work aims to develop a cost-effective emission reduction strategy by modifying the engine using conventional technologies. The present work is an experimental study of the effect of cylinder head Swirl, static injection timing (SIT), intake valve opening (IVO), and Exhaust gas recirculation (EGR) on a 0.4 l single-cylinder diesel engine's performance and emission. Baseline vehicle has HC+NOx and PM emission levels are 0.61 g/kM and 0.04 g/KM, respectively; which is higher considering existing and upcoming emission norms. The lower Swirl cylinder head,  advanced IVO timings with retarded injection timings shows an 18% reduction in NOx emission with a 3% improvement in performance at the engine dynamometer. Different EGR rates were also studied and effects were analyzed on emission and fuel consumption and emissions. EGR rate of 25% with advanced IVO of 16° with SIT of 5° and 1.9 Swirl cylinder head had shown 48% improvement in HC+NOx emissions, 20% improvement in PM emission, and 11% improvement on CO emissions at the Chassis dynamometer.

The transesterification of Amygdalus scoparia oil to biodiesel was performed and examined through the electrolysis method in the presence of KOH/Al2O3 as a heterogeneous catalyst at room temperature. A KOH/Al2O3 as solid base catalyst was prepared through the impregnation of Al2O3 with KOH solution (concentration of 25g in 100 mL deionized water). The catalyst was analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS). The transesterification key variables such as reaction time, methanol to oil molar ratio, and catalyst weight were optimized by applying the central composite design (CCD) approach. The maximum yield of 94% was obtained at the methanol to oil ratio of 10:1, catalyst weight of 1.6 wt/v%, voltage of 10 V, a reaction time of 2.30 h, 10 wt% acetone at room temperature (25 ᵒC). The characterizations of Amygdalus scoparia oil and biodiesel were specified using a gas chromatography-mass spectrometry (GC-MS) and Fourier-transform infrared spectroscopy (FTIR) analyses.

An innovative method applicable to saltmarsh habitat restoration using dredged sediment was tested. Biodegradable wooden sluice boxes were placed in eroded “pits” or pools in the damaged saltmarsh and dredged sediment was pumped to fill these pits up to the level suitable for saltmarsh flora colonisation. The sluice boxes were used to carefully control volumes and dewatering of dredged material to maximise the resultant fill level. Sediment was left to settle during periods of high tide and water was prevented from entering and mixing the deposited sludge. During low tide, the supernatant was drained off, enabling more material to be deposited. This technique helped develop a layer of substrate for pioneer halophytes to colonise, without loss of material through natural entrainment and deposition back into source sites. Increases in colonisation, consolidation, shear strength and bulk density of the newly placed sediment proved the suitability of this technique for habitat restoration.

Recent researches all across the world emphasize the threat of the increasing consumption of energy. The undeniable role of energy consumption in all stages of the life cycle of materials, including extraction, factory manufacturing, and transportation has revealed the necessity of using sustainable methods to have lower energy consumed. The whole energy of all different steps of the life cycle is called "embodied energy" and the process of assessing this embodied energy input is called "life cycle assessment” (LCA). Despite the great importance of LCA, the quantitative test of such a hypothesis has been less of a concern for previous researchers in our country Iran, and due to the lack of organized information from industrial units, such a study has also faced the difficulties of data collection. In this regard, this paper evaluates the amount of embodied energy consumption of building materials at different stages of their life cycle. To reach this goal this research evaluates the initial energy quantitatively (including different stages). More precisely, the present study, based on life cycle assessment system, quantitatively evaluates and compares energy input in different stages of cradle to gate scope, in 3 case studies: Concrete, wood, and brick. The results finally show that per ton of concrete produced 110 (kw.h) electrical energy, 35 (ton) of gas, 170 (Mj) of human Energy, and 495 (g) of Gasoline is consumed, while these quantities for per ton of Brick are 35(kw.h), 18.2 (ton), 72 (Mj) and 250 (g) and For one ton of timber produced are 900 (Kw.h), no Gas used, 170 (Mj) and 495 (g).

The Bariga section of Lagos lagoon is famous in Lagos for fishing activities. However, the safety of edible fishes sold in the place has not been evaluated for a long time. This study determined the safety of Clarias gariepinus (African catfish), which is the most frequently patronized fish species in the area. Samples of the fish and soil sediments obtained during rainy and dry seasons were subjected to atomic absorption spectroscopy to determine the levels of cadmium (Cd), lead (Pb), zinc (Zn), copper (Cu), and manganese (Mn). Afterward, the daily intake (DI), target hazard quotient (THQ), hazard index (HI), and carcinogenic risks (CR) of the heavy metals were calculated. The results showed that the levels of Cd and Pb in the fish and soil sediments were above the world health organization (WHO) permissible limits, while Zn, Cu, and Mn were normal. The DI of the heavy metals, as well as the THQ and HI, were normal. However, the CR of Cd and Pb were above the recommended limits. The heads of the fishes contained the highest concentrations of the heavy metals, DI, THQ, HI, and CR. Among the heavy metals, Cd had the highest CR. There was no significant (p > 0.05) seasonal variation in the accumulations of the heavy metals in the soil sediments. Overall, the results showed that the fish may predispose consumers to health hazards. Consequently, there is a need for heavy metal pollution control in the lagoon, to safeguard the health of fish consumers.

Coal is one of the main primary energy resources in South Africa. This energy carrier is also one of the primary indicators in the energy security of the country. This paper is aimed to examine coal consumption and environmental sustainability in South Africa by examining the role of financial development and globalization phenomena using a data set gathered from 1980 to 2017. Based on this paper’s scope, ARDL Bounds, Bavaria, and the combined Hank, FMOLS, DOLS, and frequency domain tests of the causality test are used. Bayer and Hank integration tests and ARDL constraints (with Kripfganz and Schneider’s approximations) showed a common integration between this set. Findings based on ARDL short-term and long-term estimates present that economic development improves environment preservation, while economic growth and coal consumption increased environmental degradation. The frequency-domain causality test results showed that coal consumption and financial development significantly determine the environment’s stability at different frequencies.

In this study, drinking water sources including drilled wells (DW), water tankers (WT), stabilized water tanks (SWT), and plastic bottles (PB) as sequential sample were assessed at Dhamar City, Yemen to investigate the microbial contamination and the potential risk of contamination using microbial indicators and multiple antibiotic resistance index. The sequential sample involving, 5 drilled wells, 10 water tankers, 20 water tanks, and 100 plastic bottles. The study encompassed five sequential samples. Each water sample was collected in triplicate and analyzed for E.coli as a microbial indicator and antibiotic susceptibility testing. Results indicated that all the water samples were contaminated by E.coli and total coliform exceeded the acceptable levels recommended by WHO of microbial quality of drinking water. E.coli isolates (240) showed high resistance to the tested antibiotics comprising 79.82% to ampicillin, 78.32% to gentamicin, 67.5% to ceftriaxone, 19.98% to ciprofloxacin, 18.32% to amoxiclav, and 33.34% were resistant to tetracycline. The multiple antibiotic resistance index of E. coli that showed resistant to three antibiotics ranged from 0.19 to 0.24 for all the tested samples and exceeded the threshold value of 0.2 for all samples except sequential sample 4, indicating a high risk of contamination for drinking water effected by anthropogenic activities related to urbanization, accumulation of microbial contamination during the various transferring processes of water from the source into households, as well as  misuse and greater exposure to antibiotics in humans and poultry farms, which may pose a high ecological risk to the waters.

One of the most important factors in energy consumption is environmental conditions.This study aims to examine the relationship between temperature and electricity consumption in Babolsar city in Mazandaran province. The main issue in this study is to find different patterns of relationship between temperature and electricity consumption in this city. Daily electricity consumption and daily temperature, were collected from 1 Jan 2010 to 31 Dec 2019, from the Electricity Department and the Babolsar Synoptic Station. Threshold regression method was used to find the breakpoints of the regression line between temperature and power consumption. Findings revealed there were 3 distinct thresholds in the relationship between consumption and temperature. The first threshold was about