Kinetic investigation of TiO2 mediated photocatalytic degradation of Para nitrophenol Introduction In the manufacture of dyes, medicines and pesticides, nitrophenols are widely used as chemical intermediates. These are stable, carcinogenic and toxic. Para nitrophenol(PNP) is one of them and the presence of it in the environment is harmful for the living being. The technique heterogeneous photocatalysis belonging to advanced oxidation process have proved to be one of the most effective treatment methods for the removal of pollutants from wastewater. In this process strong oxidizing agent hydroxyl radicals are produced which oxidizes a wide variety of organic pollutants into innocuous end products such as carbon dioxide, water and mineral acids………
Introduction: Sulphate ions are a part of the earth’s crust and usually occur in natural waters. Many sulphate compounds are readily soluble in water. Most of them originate from the oxidation of sulphate ores, the solution of gypsum and anhydrite, the presence of shales, particularly those rich in organic compounds, and the existence of industrial wastes. Atmospheric sulphur dioxide formed by the combustion of fossil fuels and emitted by the metallurgical roasting processes may also contribute to the sulphate compounds of water. Sulphur trioxide (SO3) produced by the photolytic oxidation of sulphur dioxide comes with water vapours to form sulphuric acid which is precipitated as acid rain or snow.
Figure 10 shows the reaction between dimethyl terephthalate and ethylene glycol. In this reaction, oxygen acts as a nucleophile and hydrogen act as an electrophile. Therefore, hydrogen pull electron from oxygen to form methanol and ethylene terephthalate is formed. INDUSTRIAL SCALE PREPARTION Polyethylene Terephthalate is produced from high purity Ethylene glycol (EG) and Terephthalic acid (TPA) or Dimethyl Terephthalate (DMT). Both processes first produce the intermediate bis-(2-hydroxyethyl)-terephthalate (BHET) monomer and either methanol in DMT process or water in TPA process.
Solar energy has the potential to reach and benefit the most vulnerable communities, because it is cheaper, faster and safer than conventional power or heat generation. The investment required is comparatively modest; the systems are set up for individual, autonomous use and therefore not dependent on large infrastructure such as distribution grids, which are non-existent in many remote
The process occurs in the stroma and it produces G3P, which is used for carbohydrates such as glucose. Light-dependent reactions, on the other hand, rely on the presence of light energy. The process occurs in the thylakoid and it produces ATP, NADPH, and oxygen as a by-product. Chlorophyll contains a porphyrin ring that allows the free movement of electrons to easily gain or lose them. It is the most abundant pigment for photosynthesis as it absorbs light from most of the spectrum and transfers the energy to the reaction center.
Chapter 1 Introduction 1.1 Renewable Energy Resources Self regenerative resources found in nature are called renewable. Energy that is resulting from natural process that is replenished constantly, Resources of renewable energy are sunlight, wind, tides and geothermal heat. Renewable energy exists continuously and abundant in the environment, ready to be harnessed, clean alternative to fossil fuels. Renewable energy put conventional energy in key four areas: Hot water/space heating, electricity production and transportation and off-grid energy services. The major renewable energy resources are the following.
………………………………………………………………………………………… 2. Renewable Energy • Renewable energy is energy which is generated from natural sources i.e. sun, wind, rain, tides and can be generated again and again as when required. • It is considered the cleanest sources of energy on this planet. Renewable sources have low carbon emissions, so they are considered environment friendly.
First, water can be held in order to provide for times of less water. No waste or pollution. Additionally, it is renewable because the water can be reused. Disadvantages : Hydroelectric energy include that the dams can be rather expensive to build. There also needs to be enough supply of water to create energy, and that supply of water needs to be powerful.