9 CONCLUSION AND RECCOMENDATIONS
9.1 Conclusions
The autoclave oxidation of sulphur, selenium and arsenic has been studied in terms of investigating the dissolution behaviour in an alkaline system. Also the mathematical description of the interfacial mass transfer rate of the primary oxidant-diatomic oxygen (O2) molecule) from the gas to the liquid phase has been evaluated. The conclusions are summarized as follows:
9.1.1 Reaction Chemistry of sulphur
In the alkaline pressure oxidation of PGM’s system, sulphur reacts with an excess of hydroxide resulting in a solution containing sulphate, sulphite, thiosulphate, polysulphides and free hydroxide ions. The sulphite ion is predominant at high oxidation potential while the other species are formed
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A number of conclusions may be drawn from the foregoing …show more content…
The reaction rate was a strong function of oxygen partial pressure with a significant increase in reaction rate with increase oxygen partial pressure. The reaction order of 0.37 for reaction with respect to dissolved oxygen concentration was obtained.
IV. The reaction rate decreased with increase in pulp density because of mass transfer limitations. The reaction rate with respect to pulp density was not obtained.
9.1.3 Reaction chemistry of selenium
Selenium is in close proximity to sulphur and the chemical behaviour is similar in many respects. In alkaline oxidation of selenium, selenite and selenate are the predominant species. However, at higher oxidation potential as is the case in this study, selenite is possibly formed as an intermediate species while selenate predominates.
9.1.4 Reaction Kinetics of selenium
Just as in the case of sulphur, kinetics of pressure oxidation of selenium was studied under various conditions in the temperature range of 160 to 190°C. The following conclusions can be drawn from the
The physical properties of sulfur are a bright yellow powder. When it is burned you will see a clear blue flame and it has a strong odor. Sulfur has a melting point of 239.38 degrees Fahrenheit, a boiling point of 832.28 degrees Fahrenheit, and the density is 2.67 g/cm. Sulfur has sixteen electrons, protons, and neutrons. When sulfur reacts with the air it produces a gaseous dioxide. It does not react with water under normal circumstances. Sulfur reacts with halogens when it is heated. Sulfur makes up almost 3 percent of the Earth’s mass. At
The purpose of the experiment is to study the rate of reaction through varying of concentrations of a catalyst or temperatures with a constant pH, and through the data obtained the rate law, constants, and activation energies can be experimentally determined. The rate law determines how the speed of a reaction occurs thus allowing the study of the overall mechanism formation in reactions. In the general form of the rate law it is A + B C or r=k[A]x[B]y. The rate of reaction can be affected by the concentration such as A and B in the previous equation, order of reactions, and the rate constant with each species in an overall chemical reaction. As a result, the rate law must be determined experimentally. In general, in a multi-step reac...
With this information we were able to identify any patterns and similarities. Hypothesis: The higher the temperature of water, potato and H²O², the rate at which the Enzyme will work will be faster therefore producing more oxygen. The reaction will be the same without the catalase (potato). Therefore in both experiments the Enzyme will work more rapidly and produce more oxygen. Aim: To test the hypothesis.
Scanning electron microscopy (SEM) technique was employed extensively through want this study to examine and obtain images of prepared samples. The associated analytical facility of Energy dispersive X-Ray (EDX) analysis was used to identify and quantify the elemental composition of the prepare samples.
at a volume of 4cm3. The preliminary work also proved to me that my basic method worked without any setbacks that may affect my results. Variables:.. The variables involved in the rate of reaction between amylase and starch are. The volume of amylase The volume of starch
-------------------------------------------------------------------- The reactivity series is a table to show which metals are most reactive to the least reactive. Potassium is known as the most reactive and platinum the least. --------------------------------------------------------------
Sulfur dioxide is a colorless gas which with a pungent odor. It will become liquid form when under pressure (heat) and will dissolves in water very fast or easily. The primary sources of sulfur dioxide are comes mainly from some activities such as burning of fossil fuel to provide electric power, process of making steel, coal-burning and others. However, it can also be released from the natural volcanic activity or volcanic eruption to the air. This gaseous can easily pose a threat to the living things such as human, animal and plant.
In this lab, it was determined how the rate of an enzyme-catalyzed reaction is affected by physical factors such as enzyme concentration, temperature, and substrate concentration affect. The question of what factors influence enzyme activity can be answered by the results of peroxidase activity and its relation to temperature and whether or not hydroxylamine causes a reaction change with enzyme activity. An enzyme is a protein produced by a living organism that serves as a biological catalyst. A catalyst is a substance that speeds up the rate of a chemical reaction and does so by lowering the activation energy of a reaction. With that energy reactants are brought together so that products can be formed.
The aim of this experiment was to investigate the affect of the use of a catalyst and temperature on the rate of reaction while keeping all the other factors that affect the reaction rate constant.
The solution for the resistance to oxidation of p-toluic acid was solved by the discovery of bromide-controlled air oxidation in 1955 that was led to the implementation of AMOCO process [28-31]. In AMOCO process, the oxidation of para-xylene was conducted using a combination of three ions as a homogeneous catalyst which is cobalt, manganese and bromide ions. Acetic acid and oxygen/air were used as solvent and oxidant, respectively [32]. The common bromide ion sources are hydrobromic acid (HBr) and sodium bromide (NaBr). The oxidation operated at 175-225°C and 15-30 bar of oxygen. The terephthalic acid formed mostly in the form of solid due to the low solubility of terephthalic acid in the acetic acid. AMOCO process successfully gives a promising reaction yield, since more than 98% of para-xylene reacted, while terephthalic acid selectivity yield was about 95% in the reaction time of 8-24 hours (Scheme 3).
Purpose: The purpose of this lab is to explore the different factors which effect enzyme activity and the rates of reaction, such as particle size and temperature.
The first experiments investigate the order of reaction with respect to the reactants; hydrogen peroxide, potassium iodide and sulphuric acid by varying the concentrations and plotting them against 1/time. An initial rate technique is used in this experiment so ‘the rate of reaction is inversely proportional to time.’ To find the order of reaction in respect to the reactants, 1/time is plotted against the concentration of Hydrogen Peroxide using the equation:
Conclusion This experiment was set out to find the effect of different temperatures of hydrochloric acid on the rate of reaction with magnesium. The information recorded was then interpreted and compared to the hypothesis. From this information, a conclusion can be made to show that the rate of reaction relates to temperature in the reaction between hydrochloric acid and magnesium. In conclusion, as proven in this experiment, the higher the temperature of hydrochloric acid, the faster the reaction it has with magnesium.
Electrolysis Investigation Planning In this investigation, I will assess how changing the electric current in the electrolysis of acidified water affects the rate at which hydrogen gas is produced. The solution to be electrolysed is made up using acid and water. It is of little consequence what acid is used however in this case I will use Sulphuric acid (H2SO4). When H2SO4 is put in water it is dissociated and forms ions: H2SO4 → 2H (2+) + SO4 (2-) Ions are also present from the water in the solution: H2O → H (+) + OH (-) During the electrolysis process, the positive hydrogen ions move towards the cathode and the negative hydroxide and sulphate ions move towards the anode.
There are five factors which affect the rate of a reaction, according to the collision theory of reacting particles: temperature, concentration (of solution), pressure (in gases), surface area (of solid reactants), and catalysts. I have chosen to investigate the effect of concentration on the rate of reaction. This is because it is the most practical way to investigate. Dealing with temperatures is a difficult task, especially when we have to keep constant high temperatures. Secondly, the rate equation and the constant k changes when the temperature of the reaction changes.