Environment & Ecosystem Science (EES)

In this study, Polyvinylidene Fluoride (PVDF) nanocomposite membrane consisting of electrospun titanium dioxide (TiO2) nanofibers (PVDF/e-TiO2) was prepared by hot pressing the as-spun TiO2 nanofibers onto PVDF flat sheet membrane. The hot press technique was carried out by applying the operating pressure at 1 bar, 1.5 bar and 2 bar for 30 seconds. The nanocomposite membrane was characterized by Scanning Electron Microscope (SEM) spectroscopy. The SEM images and analysis shows good adhesion and dispersion of TiO2 nanofibers in PVDF membrane. Based on the results, it can be concluded that a fine-tuning on the optimization study of the membrane hydrophilicity by several approaches such as pure water flux, glucose rejection and contact angle is desirable in order to ensure the developed PVDF/e-TiO2 membranes can be simultaneously efficiently functioned by means of filtration applications. Membrane successfully done glucose rejection and then COD analysis is carried out with higher efficiency. As the pressure increases the chemical oxygen demand (COD) increases because dissolved oxygen is removed in retentate side together with glucose./div>

Dye Sensitized Solar Cell (DSSC) using titanium dioxide (TiO2) has begun to play a significant role in future solar energy since it is known as cost effective and highly efficient. DSSC is the third generation of photovoltaic cells that have been widely investigated as a promising replacement of current commercial solar cell. However, the highest efficiency of DSSC still has not achieved the minimum requirement so that it can be commercialize. Much research has been done to improve DSSC performance by focusing on photoanodes layer. In this study, graphene was employed into TiO2photoanode to increase the efficiency and to enhance the performance of dye sensitized solar cell. Four different samples of nanocomposites paste were prepared by varying the graphene composition of 0.00, 0.30, 0.50 and 0.70 wt%. The prepared samples were coated on Fluorine-Doped Tin Oxide (FTO) conductive glass substrates by a doctor blade method and annealed at 450oC for 30 minutes. The morphology and structure of the graphene-TiO2 nanocomposites layer were characterized by using Field Emission Scanning Electron Microscope (FESEM). The optical properties were studied by using UV-visible spectroscopy. Based on the result show that addition of graphene into TiO2 have provide larger surface area compared to pure TiO2. The optical properties of Graphene-TiO2 nanocomposites also improved as the fundamental of absorption edge has shifted toward longer wavelength and reduce the optical band gap.

Carbon dioxide is one of the main concern in the environment when it comes to energy usage of fuel, even the fuel is coming from natural gas sources. Apart from endangered the environment, carbon dioxide also affects the caloric value of the natural gas itself. The presence of carbon dioxide as contaminants is a nuisance for oil and gas industry as its capability of forming corrosion in pipeline, thus its removal is vital for this industry. The absorption of carbon dioxide in emulsions would be an effective method to prevent corrosion. This study focused on the effects of cosurfactant, complementing 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) with surfactant which is sorbitan oleate (SPAN 80), on the stability of water-in-oil (W/O) emulsion. This study also investigates the use of blended amines which are methyldiethanolamine (MDEA)/2-amino-2-methyl-1-propanol (AMP) and MDEA as aqueous phase. A modified rotating disk contactor (RDC) was used in absorption process and gas chromatography (GC) was used to determine the amount of the CO2 absorbed. Analysis of carbon dioxide absorption through emulsion indicates that different cosurfactant may change the absorption mechanism.

This study applies a concept Microbial Fuel Cells (MFCs) in a biological cathodic protection (CP) system. The biological CP uses the microbial properties of living microorganisms which are able to produce electrons and suffice the requirement for CP in corrosion prevention system. The electrons produce by the bacteria will be diffuse and transfer to the surface area of graphite which is use as anode. The objective of MFCs for CP is to achieve an optimum value of electro potential produce by bacteria inoculated in MFCs system as preventive measures against corrosion occurred in commonly used carbon steel pipeline. The purpose of the study is to identify the wastewater derived from industry, estuary and dairy farm animal that can give the nearest optimum value of -850 mV for CP. Prior to the objective, three different types of waste is choose as samples in this study which are palm oil mill effluent (POME), estuary water and goat’s feces. Wastewater such as POME and estuary water is stored in a freezer at the temperature below 4oC. Meanwhile goat’s feces is soak in distill water for 24 hours before it is place in a freezer. After the collection of wastewater, a proximity analysis such as pH, conductivity, salinity, COD and TSS is conducted to determine the quality of the wastewater. The 4 liter of wastewater is place in a rig and 40g of sodium acetate as substrate is mix so that it will act as medium for bacteria growth in a single chamber MFCs. The backfilling for the experiment is sand with sand to wastewater is 2L and 4L respectively. The anode (graphite) will undergoes treatment to remove contamination by soaking it in a 100% ethanol for 30 minutes and then soak in 1.0 M HCl for one hour. The electro potential reading is record periodically in hourly basis using electrical multi meter for each source of wastewater and correspondent current density and power density will be determined. In the experiment, three samples is used to represents the population of each type of wastewater in order to have accurate reading and more reliable results during analysis. A statistical analysis is use for the purpose of fulfilling the objective of the study. The result of study shows that wastewater from goat’s feces gives the lowest rate of corrosion which is 1.18 x 10-6 kg/h and followed by estuary water and palm oil mill effluent of 4 x 10-6 kg/h and 7.18 x 10-6 kg/h respectively. It is also found that the wastewater from goat’s feces achieved the highest mean negative potential of -578.07 mV while standard cathodic protection is -850 mV.

Researches done prior to this study focuses on designing of pressure vessel, theoretical studies on failure modes and catastrophic accidents of pressure vessel. This study intents to analyse stress effect based on ASME VIII Division I, PD 5500, and EN 13445 and design a storage tank using PVElite. This study is done for varying internal design temperature and internal design pressure. It is limited by tank capacity, size, type, shape and orientation of pressure vessel. The external design temperature, external design pressure, head type, joint efficiency, diameter, length, and corrosion allowance are restricted as well. The study is done by selecting type of pressure vessel, code of practices, materials and design parameters before performing analysis using PVElite. A LPG storage tank was designed using PVElite. A total of twelve simulation is done and the results are tabulated. It is seen that American standard is capable of simulating for internal temperature less than external temperature which is not possible than the other two counterparts. Here, the external temperature is set at 250C and the internal temperature varies from 00C – 600C with increment of 200C. British and European standard had an error while performing simulation for 00C and 200C The American standard also has the highest value for required thickness for external thickness for head and shell with 3.36518mm and 5.45026mm for head and shell respectively. The internal thickness for American standard is also the highest with 2.5mm, 2.65822mm, 4.01886mm and 6.14440mm for head thickness at 00C, 200C, 400C and 600C respectively while shell thickness is 2.5mm, 2.66606mm, 4.03766m and 6.18855mm for 00C, 200C, 400C and 600C respectively. Stress computed for head and shell for American standard was also the highest with 19.074 MPa, 38.148 MPa, 64.429 MPa and 118.258 MPa at 00C, 200C, 400C and 600C respectively for head and 15.525 MPa, 25.772 MPa, 60.151 MPa and 102.455 MPa for 00C, 200C, 400C and 600C respectively at shell. It is concluded that American standard is the better option of the three.

The Antorun river is a flowing river situated at Onipanu village, along Ogbomoso-Iresaapa road, Nigeria. It was constructed primarily for irrigation purpose through the Nigerian-Canadian vegetation project and is under scrutiny for other purposes such as hydroelectric project, recreation, fishing and research. This study aimed at evaluating and documenting the species richness and diversity of the non-woody angiosperms along the reservoir.1m2 quadrats were placed randomly at both rainy and dry seasons to sample non-woody angiosperms along upper (site A), middle (sites B and C) and lower (site D) courses which extend to about 1 km. A total of 1526 non-woody individual plants belonging to 28 genera and 13 families were identified in the study area. 22 of the plants were medicinal while others were forage plants. The family Asteraceae had the highest number of individuals (878) representing 9 species, with Tridax procumbens being the most frequent (11.3%). The importance Value Index (IVI) of the species in the study ranged between 1.1 and 44. Sampling point B recorded the highest diversity with Si mpson’s index of 0.822 and Shannon-Wienner’s index of 1.849. The upper course of the reservoir was richest while the lower course was the poorest in species diversity and the commonest plant species in the study area was Emilia sonchifolia. Some woody species present in the study area were also identified and recorded. Information about plant diversity in this study area is useful in evaluating the potential impact of proposed developmental activities on the environment.

Physicochemical parameters are the important indicators for determining the quality of water. This study was conducted to examine the water quality of two important water bodies located in Dhaka city namely Ramna Lake and Shahidullah Hall Pond of Dhaka University. It analyzed pH, DO, EC, TDS, BOD, HCO3-, Alkalinity and salinity as well concentration of heavy metals i.e., Iron, Lead, Nickel, Silver, Mercury, Chromium, Manganese and Zinc. It is found that the pH of four samples ranged from 6.53 to 6.72 whereas DO varied from 4.18 to 5.03 mg/l, EC 1.79 µS /cm to 2.34 µS/cm, TDS 85.7 to 111.7 ppm and BOD 1.32 to 2.43 mg/l, respectively. Along with physicochemical parameters, the hardness found ranging from 52.13 mg/l to 60.76 mg/l, Alkalinity 92.35 to 96.45, HCO3-79.06 to 110.23 while CO32- not detected of these water bodies. Moreover, this study found the presence of heavy metals in these water bodies such as Lead varied from 1.8 to 3.5 µg/l, Nickel 4.5 to 6.9 µg/l, Mercury 0.001 to 1.6 µg/l, Chromium 2.0 to 2.2 µg/l and Manganese 0.03 to 0.8 µg/l respectively in which some were exceeding the Bangladesh Standard. Thus, this study is portraying the pollution problem of these water bodies and su ggesting the necessity of proper management action as early as possible.

The concept of erodibility has gained a great importance in the field of soil erosion modelling and applications of soil conservation. Soil erodibility factor has become one of the key factors which determine soil particles resistance to be detached by water erosion. This study was performed to determine soil erodibility factor and assess spatial variability of soil erodibility using geostatistics at El Hammam catchment. In this study 51 samples of surface soil (0-20cm) were collected across the study area of 1000 Ha by preparing point map at GIS. Sampling points were identified in field by a Global Positioning system. Some soil properties and organic matter were measured at laboratory, and permeability and structure were determined using soil texture analysis. Amount of soil erodibility changed from 0.16 to 0.66. The variability analysis has shown that soil properties and erodibility factor have varied significantly in cropland and have ranged from 63% in organic matter and 39% in K factor. The statistical analysis indicated negative correlations of erodibility with clay, organic matter and permeability and negative correlations of this factor with silt, sand and soil str ucture. Based on kriging interpolation method, soil erodibility factor map was generated using Ordinary Kriging. The spherical model has given the best model to predict spatial variability of soil erodibility which root-mean-square error and mean error values of interpolated map were very low. The range of the spatial dependency was equal to 460 m. The study basin has been classified as highly erodible and ecologically vulnerable.

Man arrived on the planet earth only recently i.e. about 1 million years ago! but he has been using his knowledge and technology to impact on other living organisms (the biodiversity) that have taken more than 600 million years do develop. In this review, the concept of biodiversity is considered beyond the physical/morphological manifestation of plants, animals and the microbes (i.e. species diversity), and further defined in terms of genetic, behavioral, life-history, physiological and other diversities. The paper examines the essence of biodiversity from the perspectives of food production, drug development, inexhaustible genetic resources and ecosystem services but regrets to note the unsustainable manner of its exploitation by humans. Additionally, it highlights the necessity for reducing ecological footprints (and increasing our handprints) as a way out of this environmental challenge. The paper concludes that our planet is sick, and the basis of our existence is being undermined with the onset of bi ological poverty. It therefore recommends that everyone of us should begin to use our “healing hands” to compensate for the damage we have done or are doing directly or indirectly to biodiversity.