An overview of mercury emission sources and application of activated carbon for mercury removal from flue gas / Hidayu Abdul Rani ... [et al.]

Mercury emission into the atmosphere is a global concern due to its detrimental effects on human health in general. The two main sources of mercury emission are natural sources and anthropogenic sources. Mercury emission from natural sources include volcanic activity, weathering of rocks, water movement and biological processes which are obviously inevitable. The anthropogenic sources of mercury emission are from coal combustion, cement production and waste incineration. Thus, in order to reduce mercury emission it is appropriate to investigate how mercury is released from the anthropogenic sources and consequently the mercury removal technology that can be implemented in order to reduce mercury emission into the atmosphere. Many alternatives have been developed to reduce mercury emission and the recent application of activated carbon showed high potential in the adsorption of elemental mercury. This paper discusses the ability of activated carbon and variable parameters that influence mercury removal efficiency in flue gas

Dihidroksistearinska kiselina (DHSA) visokog prinosa temeljena na kinetičkom modelu iz epoksidiranog palmina ulja

In recent years, studies related to the epoxidation of fatty acids have garnered much interest due to the rising demand for eco-friendly epoxides derived from vegetable oils. From the epoxidation reaction, there is a side reaction involving epoxide and water. This reaction produces a by-product – dihydroxystearic acid (C18H36O4, DHSA). DHSA is one of the chemical precursors in the production of cosmetic products. Therefore, a kinetic model was developed to determine the optimised epoxidation process and concentration of DHSA, where each of the reactions was identified. The kinetic rate, k parameters obtained were: k11 = 6.6442, k12 = 11.0185, k21 = 0.1026 for epoxidation palm oleic acid, and k41 = 0.0021, k51 = 0.0142 in degradation process. The minimum error of the simulation was 0.0937. In addition, DHSA yield optimisation was done through Taguchi method, and the optimum conditions obtained were H2O2/oleic acid – OA unsaturation molar ratio 1 : 1 (level 2), formic acid – FA/OA unsaturation molar ratio 0.5 : 1 (level 1), temperature 35 °C (level 1), and agitation speed 100 rpm (level 1). A high yield of DHSA can be achieved under these conditions. This work is licensed under a Creative Commons Attribution 4.0 International License.Posljednjih godina studije povezane s epoksidacijom masnih kiselina izazvale su veliko zanimanje zbog sve veće potražnje za ekološki prihvatljivim epoksidima dobivenim iz biljnih ulja. Iz reakcije epoksidacije dolazi do nuspojave koja uključuje epoksid i vodu. Tom reakcijom nastaje nusproizvod – dihidroksistearinska kiselina (C18H36O4, DHSA). DHSA jedan je od kemijskih prekursora u proizvodnji kozmetičkih proizvoda. Stoga je razvijen kinetički model za određivanje optimiranog procesa epoksidacije i koncentracije DHSA, gdje je identificirana svaka od reakcija. Dobiveni parametri kinetičke brzine, k bili su: k11 = 6,6442, k12 = 11,0185, k21 = 0,1026 za epoksidacijsku palmino-oleinsku kiselinu i k41 = 0,0021, k51 = 0,0142 u procesu razgradnje. Minimalna pogreška simulacije bila je 0,0937. Uz to, optimizacija prinosa DHSA provedena je Taguchijevom metodom, a dobiveni optimalni uvjeti su molarni omjer nezasićenja H2O2/oleinske kiseline – OA 1 : 1 (razina 2), molarni omjer nezasićenja mravlje kiseline – FA/OA 0,5 : 1 (razina 1), temperatura 35 °C (razina 1) i brzina miješanja 100 o min–1 (razina 1). Pod tim se uvjetima može postići visok prinos DHSA. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna

Formation of Dihydroxystearic Acid (DHSA) from epoxidized palm oleic acid by peracid mechanism and their kinetic study / Mohd Jumain Jalil...[et al.]

Dihydroxystearic acid (DHSA) is a product derived from a chemical modification of palm oleic acid. Application of these valuable fatty acids can be found in cosmetics, as a thickening agent and as a coating agent for pigments due to its unique structure. This study investigates the effect of a catalyst on epoxidation and the formation of DHSA by peracid mechanism. The epoxidation yield calculated by relative conversion to oxirane (RCO%) with a high yield of 95% achieved. Thereafter, the epoxidized oleic acid was hydrolyzed to produce DHSA. The formation of DHSA was verified by analysed the physicochemical properties using Fourier Transform Infra-red (FTIR). The kinetic model was being conducted to determine reaction rate using Particle Swarm (PS). The result showed that PS obtained a minimum error of 0.2005 and a correlation coefficient, r of 0.9999

Preparation of Biopolymer from Musa Acuminata (Banana) Peels

The banana fruit’s peel was selected as it is a waste material rich of starch. In particular, starch is one of the most attractive feedstock for the development of biodegradable polymers because it is relatively inexpensive, abundant and renewable. Thus, starch-based can be a replacement for conventional plastics which is becoming decrease.  The starch consists of two different types of polymer chains, which called amylose and amylopectin, made up of adjoined glucose molecules. Chemicals such as sodium hydroxide (NaOH), hydrochloric acid (HCl), Glycerol and sodium bisulfite (NaHSO3) were prepared since they are the most helpful agent for the formation of bioplastic film. The hydrochloric acid was used to remove the part of the starch which is amylopectin that will inhibit the formation of a film. The sodium hydroxide (NaOH) was used in the experiment for the starch neutralization and glycerol acts as a plasticizer which make the plastic less brittle. In order to improve the shelf-life, sodium bisulphite (NaHSO3) was added as an antimicrobial. Analysis such as water absorption was observed to determine the physicochemical properties of the biopolymer prepared. From experimental results showed that sample 1 seemed to have the strong cross-linked structure which it absorbed the lowest percentage of water of about 56.95%. This result may due to phase separation and crystallization of glycerol by making the film more soluble which high in absorption capacity and also affected by the concentration of NaOH and HCl in the biopolymer

Optimization of Precious Metals Recovery from Electronic Waste by Chromobacterium violaceum Using Response Surface Methodology (RSM)

An effective recovery technology will be valuable in the future because the concentration of the precious metal contained in the source can be a key driver in recycling technology. This study aims to use response surface methodology (RSM) through Minitab software to discover the optimum oxygen level (mgL−1), e-waste pulp density (% w/v), and glycine concentration (mgL−1) for the maximum recovery of gold (Au) and silver (Ag). The method of precious metals recovery used for this study was taken from the bioleaching using 2 L of batch stirred tank reactor (BSTR). A Box-Behnken of RSM experimental statistical designs was used to optimize the experimental procedure. The result of the RSM optimization showed that the highest recovery was achieved at an oxygen concentration of 0.56 mgL−1, a pulp density of 1.95%, and a glycine concentration of 2.49 mgL−1, which resulted in the recovery of 62.40% of Au. The pulp density and glycine concentration greatly impact how much Au is bioleached by C. violaceum. As a result, not all of the variables analyzed seem crucial for getting the best precious metals recovery, and some adjustments may be useful in the future