Controlling Water Temperature during the Electrocoagulation Process Using an Innovative Flow Column-Electrocoagulation Reactor

A flow column has been innovatively used in the design of a new electrocoagulation reactor (ECR1) that will reduce the temperature of water being treated; where the flow columns work as a radiator for the water being treated. In order to investigate the performance of ECR1 and compare it to that of traditional reactors; 600 mL water samples with an initial temperature of 350C were pumped continuously through these reactors for 30 min at current density of 1 mA/cm2. The temperature of water being treated was measured at 5 minutes intervals over a 30 minutes period using a thermometer. Additional experiments were commenced to investigate the effects of initial temperature (15-350C), water conductivity (0.15 – 1.2 mS/cm) and current density (0.5 -3 mA/cm2) on the performance of ECR1. The results obtained demonstrated that the ECR1, at a current density of 1 mA/cm2 and continuous flow model, reduced water temperature from 350C to the vicinity of 280C during the first 15 minutes and kept the same level till the end of the treatment time. While, the temperature increased from 28.1 to 29.80C and from 29.8 to 31.90C in the batch and the traditional continuous flow models respectively. In term of initial temperature, ECR1 maintained the temperature of water being treated within the range of 22 to 280C without the need for external cooling system even when the initial temperatures varied over a wide range (15 to 350C). The influent water conductivity was found to be a significant variable that affect the temperature. The desirable value of water conductivity is 0.6 mS/cm. However, it was found that the water temperature increased rapidly with a higher current density

Experimental characterisation of non-encapsulated bio-based concrete with self-healing capacity

The main reason for early corrosion in Reinforced Concrete (RC) structures is crack formation within the concrete cover. Cracks can lead to leakage problems, allowing chloride, oxygen, water and other aggressive chemicals to enter into concrete and eventually causes corrosion of steel reinforcement. The paper shows some results of a novel bio concrete with biological self-healing agent, which added into the concrete mixture, autonomously and actively, inhibits the concrete cracks and potential premature reinforcement corrosion. Two compositions of concrete samples were prepared and casted – CEMI and CEMIII with 60% of Ground Granulated Blast Furnace Slag (GGBS) with and without non-encapsulated bio-product utilising iron respiring bacteria. The developed bio-mineral is capable of sealing cracks and blocking pores resulting in a delay of waterborn ions in RC structures, acting as a diffusion barrier of oxygen to protect steel reinforcement's passivity towards corrosion. The fresh test results show that these concretes have the potential to be used in RC heavily reinforced and manually compacted sections with vibrations. The water absorption velocity has been significantly reduced with the inclusion of bio-agent in CEMI and CEMIII concretes samples, which was associated with pores sealing. Maximum water absorption via capillary tends to reduce at least 25% when bio-agent was introduced to concrete type CEMIII. Other results emphases the efficiency of the bio-product in CEMIII medium. The bio-agent does not decrease the compressive strength of tested concretes either for CEMI and CEM III. SEM observation shows that the crystals were well developed near the surface of the crack

Improving biodiesel yield of animal waste fats by combination of a pre-treatment technique and microwave technology Renewable Energy

Recently, due to its low cost there has been increased attention on Animal Waste Fats (AWFs) as a feedstock for biodiesel production. Advanced microwave technology has also been reported by many researchers to enhance the transesterification in biodiesel production. However, esterification of free fatty acids in the feedstock reported here has not attracted so much attention. AWFs come with its challenges namely, high free fatty acid (FFA) content and high water content. This study utilizes AWFs (tallow) containing very large amount of FFA; (25wt.%, 18 wt.%, and 9.4 wt.% FFA/AWFs) as feedstock for fatty acid methyl ester (FAME) production. A simple thermal pre-treatment technique followed microwave assisted esterification with methanol (MeOH) was conducted in a batch process to reduce the FFA content to as low as 1wt.% FFA, which is then suitable for the alkaline transesterification process. The pre-treatment of AWFs at 88°C to first reduce water and decrease viscosity, followed by an operating microwave power of 70W producing a power density 1.147mW/m3, achieved a 15% increase in reduction of FFA over 30W microwave power and conventional thermal method. Under optimum conditions, using 2.0 wt.wt% sulphuric acid catalyst/AWFs and 1:6 molar ratio AWF/MeOH, the FFA conversion of 93wt. % was achieved. The results indicated that the pre-treatment and microwave application provided a faster route to high FFA reduction of AWFs during esterification process. The proposed technology is promising for the potential scale up industrial application

Influence of electrodes spacing on internal temperature of electrocoagulation (EC) cells during the removal (Fe II) from drinking water

The electrocoagulation (EC) method, which is in situ generation of coagulating ions by applying direct electrical current to metallic electrodes, has recently been applied to remove a wide spectrum of pollutants from waters and wastewaters. However, its efficiency is highly influenced by key operational parameters such as electrolysis time and current density. Therefore, the current investigation has been carried out to explore the influence of electrodes spacing on the performance of EC method in terms of internal temperature iron removal from drinking water. To achieve the planned target, iron containing synthetic water samples were electrolysed, for 25 min, using a flow column electrocoagulation reactor (FCER), at three different distances between electrodes (5, 10, and 20 mm). The progression of temperature of water being treated was measured at 5 minutes intervals over a 25 minutes period. These batch experiments were commenced at a constant current density of 1.5 mA/cm2 and initial pH of 6. The results obtained showed that the amount of produced heat is directly proportional to the DBE, where it has been noticed that the water temperature increased by about 9% as the distance between electrodes increased from 5 to 20 mm, respectively

Identification of Optimal Frequencies to Determine Alpha-Cypermethrin using Machine Learning Feature Selection Techniques

Machine learning feature space reduction techniques allow for vast feature spaces to be reduced with little loss or even significant improvements in the reliability of predictions of models. Microwave spectroscopy with feature spaces of over 8000 are not uncommon when considering magnitude and phase. Applying Machine learning techniques to this type of feature space allows for a quicker reduction and helps to identify the most suitable predictive features. The control of insect vectors that transmit diseases including malaria, visceral leishmaniasis and zika rely on the use of insecticide. These diseases affect millions, malaria alone accounted for 214 million new cases resulting in 438, 000 deaths in 2015. One method used in controlling the vectors is through indoor residual spraying, applying insecticide to the wall surface inside houses. Alpha-cypermethrin is one of the insecticides that is currently sprayed in several countries for vector control. Quality assurance and monitoring of the control activities is challenging relying on the use of laboratory-reared insects. This was improved with a chemical based Insecticide Quantification Kit, but these assays have been challenging to operationalise. An electromagnetic sensor is being developed to investigate the potential to detect alpha-cypermethrin. Preliminary experiments were carried out to differentiate tiles sprayed with Technical Grade alpha-cypermethrin, wettable powder containing 5% alpha-cypermethrin and wettable powder with over dose of alpha-cypermethrin using a horn antenna at a frequency range between 1 GHz to 6 GHz. The experimental results indicated the potential use of electromagnetic waves to determine alpha-cypermethrin in a non-destructive manner