Bioremediation of oil from domestic wastewater using mixed culture : effects of inoculum concentration and agitation speed

The volume of oil in domestic wastewater is increasing each year due to the urbanization and industrial development all around the world. It is concerned that the increasing of oil in the wastewater could cause severe impact to the environment and to human health. Bioremediation of oil from domestic wastewater using mixed culture is being studied to overcome this problem. Microorganisms from local palm oil plant are utilised for this study. The ability of the microorganisms to degrade the oil is observed by investigating effect of concentration of the inoculum (g/ml) and the agitation speed (rpm) on oil removal. The optimum condition for these microorganisms to degrade oil is aimed for the highest volume of oil degraded. From the result obtained it is show that agitation with the speed of 150 rpm give the best condition for oil removal while the addition of 4g/110ml of inoculum concentration over wastewater and oil volume give the optimum oil removal. Higher concentration of inoculum cause high oil removal but at highly concentrated inoculum could cause reverse effect. Therefore high agitation also contributes to higher oil removal

Synthesis Of Large Area Graphene And Graphene Flake Via Chemical Vapor Deposition Using Copper Catalyst And Methane

Graphene is a two-dimensional material arranged in hexagonal honeycomb structures and is a single layer of graphite. Several fascinating properties of graphene such as a very conductive and highly transparent material is expected to contribute significantly towards the advancement of electronics, solar cell, composites, and medical sector. In this study, atmospheric chemical vapour deposition (APCVD) was used as synthesis method. Methane was used as carbon feedstock, nitrogen as a carrier gas and hydrogen as reducing agent for two types of graphene synthesis which is large area graphene (lateral size >1 cm2) and graphene flakes (lateral size 125 sccm) hydrogen flow rates were supplied. The locations of the catalyst at zone 1 and zone 2 of the horizontal furnace show good graphitic structure formation while at zone 3 amorphous carbon formation is more dominant. N-heptane is found as a useful material for large area graphene transfer that reduces contamination on graphene surface. Cu from etching solution waste can be reused for CuO formation and graphene flakes synthesis using a similar method for synthesis of large area graphene. In conclusion, the catalyst locations in the horizontal CVD and hydrogen flow rates play an important factor in graphene formation. The transfer method using the n-heptane as support layer assisting in graphene transfer process that reduces contamination and damage to graphene structure. Also, the graphene flakes have been successfully synthesized using the CuO / MgO catalyst obtained from recovered Cu

Characterization of defect induced multilayer graphene

A study of oxygen plasma on multilayer graphene is done with different flow rates. This is to allow a controlled amount of defect fabricated on the graphene. Results from the study showed that the intensity ratio of defect between D peak and G peak was strongly depended on the amount of oxygen flow rate thus affected the 2D band of the spectra. The inter-defect distance LD ≥ 15 nm of each sample indicated that low-defect density was fabricated. The surface roughness of the multilayer graphene also increased and reduced the conductivity of the multilayer graphene

Formulation of water-based white colour paint from waste titanium dioxide

This work explains the production and synthesis of white paint pigment colour from waste titanium dioxide (TiO2). Pigments are widely employed in paper, plastic, and paint production. A white pigment called TiO2 is responsible for about seventy percent of pigments used today. Even though minerals that contain TiO2 within the earth's crust are relatively abundant, the production of virgin TiO2 for industrial application consumes enormous energy and can lead to an environmental problem. Hence, a need arises for the paint industry to seek an alternative to replacing virgin TiO2 pigment that is commonly utilised in formulating paints. This study was conducted to examine the probability of using secondary TiO2 pigments as an alternative to virgin pigments to formulate white paint from industrial waste. In this study, the prospect of using waste TiO2 to formulate white paint pigment in different ratios is compared with the paint industry. The paint industry and TiO2 pigments were characterised by utilising thermo quantitative analysis TGA, XRD, and FTIR analysis. The obtained result showed 20% TiO2 formulated paint provide the best result for the adhesion test that testify the optimum pH and viscosity for the paint with the classification of 3B which is comparable to paint industry performance

A Novel Hybrid Full Adder using 13 Transistors

Full adder is a basic and vital building block for various arithmetic circuits such as multipliers. In this paper, a hybrid 1-bit full adder using complementary metal-oxide semiconductor (CMOS) logic style had been designed. This hybrid adder divided into three modules. Module I is a three transistors XOR gate. Module II is a novel sum circuit which successfully modified with the usage of lesser number of transistors used. Module III is a carry circuit which uses the carry output of module I and several other input to generate carry output. Performance parameters such as power and delay were compared to some of the existing designs. With a 1.8V voltage supply, the average power consumption of proposed hybrid adder was found extremely low which is 2.09 μW and a very low delay of 350 ps. Design in both speed and energy consumption becomes even more significant as the wordlength of the adder increases. The full adder design is simulated using Tanner EDA version 16 using General Process Design Kit (GPDK) 250nm technology CMOS processes

Synergistic effect of molybdenum disulphide and butylated hydroxytoluene in lithium complex grease

Lubricating grease is vital as a sealant and provides extra protection for automotive parts, such as bearings. Bearings are subjected to friction and sliding wear, which results in the degradation of automotive or machinery performance. The present article analysed the effect of molybdenum disulphide (MoS2) and butylated hydroxytoluene (BHT) as grease additives in reducing the frictional and wear behaviour of steel ball bearings. The experiment was conducted by preparing two formulated lithium complex-based grease with a different blending of additives of BHT only (LCG 01/18) and MoS2 + BHT (LCG 01/5). The formulated greases were compared with two industrial greases as the controlled parameters. Next, the physical characterization of formulated and industrial greases was conducted which includes dropping point test (ASTM D2265-00), cone penetration test (ASTM D217-02) and oil separation test (ASTM D6184-17). Then, the four-ball test (ASTM D2266-01) was performed to identify the effect of additives on the wear and frictional coefficient behaviour. The blending of MoS2 and BHT improves the physical characterization of grease in terms of dropping point and oil separation. The blending of MoS2 and BHT also helps to decrease the wear diameter and frictional coefficient. Nonetheless, further study is desired to gain a thorough understanding of the processes so that an optimal system can be developed for the industry

Comparison of natural adsorbent for emulsified wastewater treatment

Oil emulsion is often generated from machining industries, such as computer numerically controlled (CNC) machines and palm oil mill effluent (POME). The current study presents the adsorption strategy in treating the waste emulsion from CNC machines and POME using activated carbon, corncob, and rice husk. To evaluate the adsorbent performance, a jar test apparatus was used with the addition of the adsorbents for treating waste emulsion at the mixing rate of 100 rpm, mixing time of 30 min, and room temperature. The collected wastewater samples were characterised and analysed for chemical oxygen demand (COD), biological oxygen demand (BOD), oil and grease (O&G), and total suspended solids (TSS). Five dosages of activated carbon, corncob, and rice husk were used in the study (i.e., 2, 4, 6, 8, and 10 wt. %) with the control (0 wt. %). The study showed that rice husk and activated carbon managed to reduce pollutants in the emulsified wastewater. Thus, rice husk and activated carbon are suitable for treating industrial waste emulsion

Remediation of aquaculture effluents using physical treatment

The wastewater of the aquaculture industry contains harmful pollutants that have harmful effects on aquatic life and population. The main concern is the high values of biological oxygen demand (BOD), chemical oxygen demand (COD), and ammoniacal nitrogen in wastewater, which do not comply with the Environmental Quality (Industrial Effluents) Regulations 2009 under the Environmental Quality Act (1974), the Department of Environment (DOE), Malaysia. This study aims to evaluate the efficiency of natural and commercial wastewater treatment of aquaculture wastewater. Two natural reagents (activated carbon (AC) and MNRg-Treat powder) and a biological coagulant (MNRg-Treat liquid) were used to treat aquaculture wastewater samples. Nine beakers were used in this treatment, and 1.5 L of wastewater samples from the shrimp, tilapia, and patin ponds were poured into three beakers. After that, 7.5% by weight of each reagent was added to 1.5 L of wastewater for each sample and left for three days without mechanical assistance. Then, five parameters were analyzed for the samples in each beaker: pH, BOD, COD, dissolved oxygen (DO), and ammoniacal nitrogen. The results showed that AC is the best material to reduce ammoniacal nitrogen. The ammoniacal nitrogen level of the tilapia pond reduced by 58.82% and the patin pond reduced by 30.77% using AC, followed by 17.64% reduction using MNRg-Treat liquid for the tilapia pond. Meanwhile, MNRg-Treat powder recorded 5.88% reduction for the tilapia pond. The obtained results showed that the treatment agents demonstrated their best performance at 7.5 wt. %

Combination of cellulose tissue paper and bleach-treated graphene in stiffness reinforcement of polyvinyl alcohol film

A pre-treatment of graphene with bleach is considered one of the possible purification methods after liquid-phase exfoliation. However, the effect of this treatment on the mechanical reinforcement strategy for polymer film is yet to be investigated to date. In this full work, the influence of the C/O ratio, ID/IG, and volume of graphene after combination with cellulose tissue on the resulting stiffness of polyvinyl alcohol (PVA) composite film has been extensively studied. It is noticed that the incorporation of 30 ml graphene that had been pre-treated for 3 h into PVA had produced the best increment in elastic modulus (1.6 GPa against 0.4 GPa) while a shorter pre-treatment duration of graphene (1 h) would require more graphene volume (40 ml) to match the previous stiffness improvement level. By using the collected experimental data (90 samples), we further modeled the effect of tissue and PVA mass, C/O ratio, ID/IG, and graphene volume on modulus using machine learning (ML) algorithms

Combination of cellulose tissue paper and bleach-treated graphene in stiffness reinforcement of polyvinyl alcohol film

A pre-treatment of graphene with bleach is considered one of the possible purification methods after liquid-phase exfoliation. However, the effect of this treatment on the mechanical reinforcement strategy for polymer film is yet to be investigated to date. In this full work, the influence of the C/O ratio, ID/IG, and volume of graphene after combination with cellulose tissue on the resulting stiffness of polyvinyl alcohol (PVA) composite film has been extensively studied. It is noticed that the incorporation of 30 ml graphene that had been pre-treated for 3 h into PVA had produced the best increment in elastic modulus (1.6 GPa against 0.4 GPa) while a shorter pre-treatment duration of graphene (1 h) would require more graphene volume (40 ml) to match the previous stiffness improvement level. By using the collected experimental data (90 samples), we further modeled the effect of tissue and PVA mass, C/O ratio, ID/IG, and graphene volume on modulus using machine learning (ML) algorithms