nZVI possesses a large removal capacity, fast kinetics and high reactivity for the degradation/removal of many environmental pollutants (Chen et al., 2012; Chen et al., 2013). It has also been confirmed in previous studies that nZVI has higher absorption and enhanced reactivity for Cr(VI) removal (Zhang et al., 2013) compared to other materials (Montesinos et al., 2014). However, bare nZVI are prone to rapid agglomeration leading to the formation of micro-sized aggregates which lead to loss in reactivity and reduced in the environmental mobility (Grieger et al., 2010). This is attributed to their rapid oxidation, magnetization and high reactivity (Zhang et al., 2013; Zhou et al., 2015). One of the proposed method to overcome this drawback is to coat the nZVI particle surface with surfactants, upon rapid desorption of surfactants into the waste water the particle stability would markedly reduce.
4.1 Distillation Column Design (Hazel Villarosa Victorio -1415939) 4.1.1. Introduction and design statement Chemical engineers have a part to play in achieving sustainable goals. Since natural resources are scarce and depleting, improvement of chemical processes is important. Recovering and reusing raw materials to convert into finished products is one of such simple techniques. In production of Acetone through Isopropanol, this goal of recovering and reusing of materials can be achieved.
Sulphuric acid One of the most important chemicals used in the industrial revolution was sulphuric acid (H2SO4), as it had many different uses in textile and metallurgical industries. Due to its importance, it was in high demand and the amount which could be produced was constantly trying to be improved.It was during this period that a scientist by the name of John Roebuck discovered that this chemical could be produced at a much larger scale than once thought. He did this by making small changes to the production method. Up until now the chemical had been produced in glass bottles by reacting sulfur with potassium nitrate, or saltpeter as it was more commonly known, with steam. The potassium nitrate acted as an oxidizing agent, oxidizing
This is important because citrate ions complex iron and inhibit the formation of an oxalate precipitate. The formation of a precipitate film could interfere with subsequent exams. Ferric nitrate, ferric sulphate and diethylthiourea are often used as corrosion inhibitors to prevent pitting of carbon steel surfaces. CITROX is usually applied for eight hours at 80 oC. Despite of many good results obtained with CITROX processes, a replacement for this process has been studied especially in Czech Republic and Slovakia.
They have a relatively high level of hydrophilicity. Conversely, cationic surfactants such as cetyltrimethyl ammonium bromide (CTAB) release a positive charge in an aqueous solution. On the other hand, in alkali pH, amphoteric surfactants act as anionic while in acid pH, it act as cationic. Non-ionic surfactants such as partially hydrolyzed PVA (polyvinyl alcohol) have no charge (Li et al, 2008). Among four types of surfactants, partially hydrolyzed PVA is most frequent used because it gives the smallest microsheres (Jeffrey et al, 1991).
Phosphoric acid was used in the synthesis to become a source of H+ ions that would catalyze the reaction. Phosphoric acid is a liquid that doesn 't contain much water, since water will cause side reactions and reduce the yield of acetylsalicylic acid. A side reaction is the production of acetic acid from the water in phosphoric acid reacting with the acetic anhydride. Another reason for the use of phosphoric acid is that it creates a relatively strong conjugate base, since the acid catalysis step needs to be reversible. Sulfuric acid is also used in acetylsalicylic acid synthesis since it is 98% pure.
Sakka and co-workers first employed sol-gel method to prepare HAp. It is well recognized that sol-gel techniques have several benefits for producing ceramic particulates amid high purity, high crystallinity, and controllable grain size with good scalability. Sol-gel process, though, has a few drawbacks such as the need of costly precursor resources and little homogeneity of the finishing product. We report, herein, a cost effective sol-gel method for the gram-scale synthesis of hydroxyapatite nanoparticles using inexpensive starting materials of less toxicity. 5.1.2
When pH is high which means more OH⁻, then aluminum ions will react with hydroxide ions to form aluminum hydroxide. Phosphate ions are acting as a natural buffer. If the equipment is not washed with acid, it would cause an error. This is because the phosphorus analyzing is dealing with low concentration of phosphorus and it is easily contaminated by detergent and other chemicals and it has to be washed by using an acid and also it has to be rinsed with distilled water once it is rinsed with acid. Also refer to section 4 (discussion).
The CO2 sequestration technologies can be divided into physical and biological strategies. . One physical method to capture CO2 is in deep oceans, gas wells and aquifers. Physical CO2 sequestration has some disadvantages of high cost and capturing and storage is also very expensive process. Another method is chemical sorption of CO2power plants.
Over these few decades, fossil fuel reserves are depleting in a fast rate due to continue usage and the rising price of crude oil have triggered the energy crisis all over the world. However, in order to overcome this problem, biomass which is derived from renewable materials has become a new alternative of fuel to replace the traditional fossil fuels. Biodiesel or fatty acid methyl ester (FAMEs) which is derived from vegetables oil or animal fats is considered one of the best biomass-fuel to replace fossil fuel. Biodiesel is a renewable energy, lack aromatic compounds, highly biodegradable, and also has low SOx emission (Nyoman Puspa Asri, 2012). Biodiesel has gained the attention internationally as an alternative fuel since it is highly