1. INTRODUCTION
Environmental problems related with hazardous wastes and toxic water-pollutants have attracted much attention towards itself. Organic dyes are one of the major groups of pollutants in wastewaters released from textile and other industrial processes.
Photocatalysis is a simple and promising technique for solving various current environmental issues. Semiconductor absorbents offer a great potential for eliminating the organic pollutants present. Semiconductor photocatalysts for example, zinc oxide and titanium oxide have been applied to degradation of contaminants in waste water and air.
On common example,For photocatalysis process, ZnO has also been considered as a suitable alternative for TiO2 due to The band-gap energy of ZnO is similar to TiO2, the most used photocatalytic material, so it hypothetically has the same photocatalytic ability as TiO2 and it exhibits better performance in the degradation of organic dye molecules in acidic as well as basic media.
The doping of Cu in ZnO is expected to modify absorption, and other physical or chemical properties of ZnO also.
Lately,( Co- doping) doping of two types of atoms into semiconductor materials has attracted interest, as it result in a higher photocatalytic activity and special characteristics compared with that of single element doping into semiconductor oxides .
Here, a simple Physical method is developed for the synthesis of Cu doped ZnO nanorods, and their photocatalytic activities with different
Due to this fact, the concentration of copper in the solution is able to be calculated by using light absorbance. Since zinc doesn’t absorb any light, we are able to deduce that the greater the absorbance, the greater the concentration of copper.
The purpose of this lab was to determine the empirical formula of copper oxide compound. In the lab, hydrochloric acid and copper oxide compound was mixed until it formed a blue solution. An oxidation-reduction reaction, a reaction in which there is an exchange of electrons between elements, was performed by adding zinc to the solution to displace the copper in copper chloride. Zinc, in this case, was oxidized by losing two electrons (0 → 2+) while copper was reduced by gaining two electrons (2+ → 0). Also, when the copper was displaced, it became a precipitate, which is a substance that comes out of a solution as a solid due to insolubility.
The purpose of the experiment is to cycle solid copper through a series of five reactions. At different stages of the cycle, copper was present in different forms. First reaction involves reaction between the copper and nitric acid, and copper changed from elemental state to an aqueous. The second reaction converted the aqueous Cu2+ into the solid copper (2) hydroxide. In the third reaction Cu(OH)2 decomposed into copper 2 oxide and water when heated. When solid CuO reacted with sulfuric acid, the copper returned to solution as an ion (Cu2+). The cycle of reactions was completed with the reaction where elemental copper was regenerated by Zn and Cu
This is largely because they are relatively cheap and simple to manufacture. Furthermore, they produce vibrant shades of color and are reasonably soluble in water (Liu, Wan, Nan, n.d.). However, these dyes are now manufactured at such a large scale that they bring up numerous health and environmental concerns. In recent years azo dyes, especially Allura Red AC, have been connected to child hyperactivity, which also raises concerns over other potentially toxic effects they can have on living organisms (“FDA Probes Link”, 2011). This is only amplified by the fact that azo dyes such as Allura Red AC and Azo Grenadine are also especially recalcitrant to conventional methods of wastewater treatment. Research on this topic led me to an article on electrochemical advanced oxidation processes and their potential as a solution to mineralizing especially recalcitrant compounds in the environment, "Decontamination of Wastewaters Containing Synthetic Organic Dyes by Electrochemical Methods: A Review." This led me to pursue the investigation in my extended essay on the topic of electrochemical advanced oxidation processes and the effect they have on azo dyes such as Allura Red AC and Azo Grenadine. In order to evaluate the effect of this process, I made the decision to do a comparison of the two dyes. This led me to the question, “How does the effect of electrochemical advanced oxidation processes vary between Allura Red AC and Azo
Since these dyes are harmful to the environment, a benefit of doing research on them is to find a way to more safely and quickly remove these dyes from the environment. The current methods are expensive, and cause the dyes to turn into sludge, which is also dangerous because this sludge can produce toxic products.^3 In addition to this, doing research on the properties that these dyes have on humans would be beneficial in studying the effects they have on humans and how to treat these effects.
In the contexts of history and research, interest in heterogeneous photocatalysis can be traced back to many decades when Fujishima and Honda discovered in 1972 the photochemical splitting of water into hydrogen and oxygen in the presence of TiO2 From this time, extensive research, much of it published, has been carried out to produce hydrogen from water in oxidation reduction reactions using a variety of semiconductor catalyst materials. With respect to a semiconductor oxide such asWO3, photocatalytic reactions are initiated by the absorption of illumination with energy equal to or greater than the band gap of the semiconductor. This produces electron-hole (e−/h+) pairs as in Equation (1.14), Figure
CdSe/CdS core/shell nanocrystals were prepared by organometallic method [26] using Cadmium oxide (CdO 98.9%) was provided by Fluka. Sulfur powder (S 99.5%), Selenium powder (Se 99%), Trioctylphosphine oxide (TOPO 97%), Trioctylphosphine (TOP 90%) Hexadecylamine (HDA 97%) were purchased from Aldrich. Stearic acid 98%, Acetone 98%, Oleic acid (OA) 98%, Methanol 99%, Toluene 99% were from united chemical Lab. All chemicals and solvents had been used as received while not more purification. In the experiment, OA was used as the ligand of and TOP was used as the ligand of the Se precursor.
The prepared zinc powder could easily be removed from the cathode surface and was washed in distilled water for several times until all possible existing alkaline solution was removed from the powder particles. This was proved by addition of few droplets of phenolphthalein to the ablution water. After that, the powder was treated with an alcohol-acetone mixture (ethanol-acetone = 1:1) to remove water, then dried for 2 h in 100 °C, weighed, and stored in a polyethylene plastic bag to avoid further oxidation. A different weight of Zn powder was obtained in each experiment, the current efficiency (CE) was calculated using Eqs. (1) and (2) as follows:
Background and Objective: the human activities generate a variety of contaminants. One of these contaminants is the pesticides which are used to exterminate the agricultural pest. Organophosphates are a class of pesticides which, were replaced with the organochlorines from a few decades ago, due to their less resistance. diazinon is one of Organophosphate insecticide which is classified as a relatively hazardous materials (Class II by the World Health Organization). Diazinon has many adverse effects such as disruption of the immune system (Immunotoxic), cytotoxicity and Genotoxicity. The insecticide is relatively soluble in water and the maximum remaining level in water is 1 mg/L. The release of diazinon into surface and groundwater resources is one of important worries. Several methods such as ultrasonic waves, biodegradation, optical degradation, ozonation, gamma rays, Fenton, UV / H2O2 and Photocatalytic degradation have been used to remove the diazinon. The complexity of the process, high cost and high consumption of chemicals are of the problems with these methods. Nano-photocatalytic methods are new developing methods to remove environmental pollutants. TiO2 has found more attention due to high photocatalytic activity, stability against the light corrosion, economic acceptability and lack of
Zinc is currently the fourth most widely consumed metal in the world after iron, aluminum, and copper. In nature, zinc ores could be divided into sulphide minerals and oxide minerals. Zinc is extracted mostly from zinc sulfide ores. With depletion of global resources of zinc sulfides as well as the restriction on sulfur emissions during their processing, there is an increasing focus on the processing of the huge reserves of zinc oxide ores (Li et al., 2010).
By sеvеral diffеrеnt mеthods, including mеtal-organic vapour phasе еpitaxy (MOVPЕ), molеcular bеam еpitaxy (MBЕ) and pulsеd lasеr dеposition (PLD), thе ZnO еpitaxial layеrs and quantum wеlls havе bееn grown. Thе growth in c-axis oriеntеd dеspitе growth on a rangе of singlе crystal substratеs, including ZnO, sapphirе and Si oriеntеd along various crystal
80% of all the zinc utilized today will be reused eventually. Because of the long life expectancy of many zinc items – more than 100 years now and again – a significant part of the zinc utilized as a part of the past is still in administration. Zinc reusing innovation is progressing and the supply of zinc accessible for reusing is developing as well. Zinc can be reused uncertainty, without loss of its physical or substance properties, in this way constituting a significant and economical asset for future eras. Zinc is utilized to cleanse water, along these lines contributing a little answer for one of the colossal natural issues of the planet. Recyclable zinc-air batteries effectively control electric vehicles, offering another answer for the issue of urban air quality. Zinc is a noteworthy constituent of metal, a well being defensive metal because of its bacteriostatic qualities. Zinc is a vital pharmaceutical fixing, giving everyday healthy skin and assurance against the destructive beams of the sun. Zinc is required in manures that support edit yields thus bolster the world's developing populace. What's more, zinc is available regular, wherever in our homes and family unit apparatuses, fittings, instruments and toys, in our workplaces and PCs, our autos, prepares and
All chemicals were of analytical grade. Electrolytic zinc powders were produced by electrolysis of alkaline solutions containing zinc oxide. These solutions were prepared by dissolving a given amount of ZnO in 6 mol L-1 NaOH. After complete dissolution, solutions were stored in 500 ml volumetric flasks. Removing of water from the prepared zinc powder was performed using analytical grade ethanol and acetone mixture.
The doping of semiconductor by rare earth metal nanoparticles is an effective way for increasing in photocatalytic activity. Zinc oxide and Lanthanum doped Zinc oxide nanoparticles were synthesized by modifying the gel-combustion method. It was found that La can greatly enhance the cytotoxicity and photocatalytic activity of ZnO nanoparticles towards various cell lines and paracetamol drug. These nanoparticles were characterized by various spectroscopic and other techniques which clearly revealed the presence of lanthanum ions. The UV-vis spectroscopy displayed the absorption edge shifts towards the visible region after doping with La which is extremely favorable for absorbing the visible light. We compared the enhancing effect of La ions and found that La doped ZnO nanoparticles is more effective than ZnO nanoparticles in promoting the generation of hydroxyl radicals, holes and the photocatalytic activity of
Thus, numbers of articles devoted to ZnO photoelectrode with the aim to enhance efficiency by reducing the charge carrier recombination, and improving electrical/optical performance [9-12]. In this regard, doping is the most advantageous approach to modify ZnO structures. Different kind of metals such as lanthanum [13], aluminum [14], tin [15], magnesium [16] and titanium [17] has been widely investigated as effective dopants in ZnO photoelectrode for improving the performance. Moreover, earlier reports on the DSSC have proven that the active area is directly proportional to the power conversion efficiency [18]. Therefore, we attempted to incorporate indium into ZnO to improve above cited aspects with an ideal working area (0.25cm2) of photoanode in DSSC. Indium (In3+) was chosen as dopant, because it has a noteworthy contribution in transparent conducting oxide materials and much work devoted in indium doped ZnO as a transparent conducting oxide film [19-20]. Owing to their remarkable properties such as high electronegativity, minute native lattice distortion with preferable chemical stability make indium as suitable donor than other elements for finding high quality ZnO based transparent conducting oxide with an excellent conductivity in DSSCs [21]. Rama Krishna Chava et al. used In doped ZnO nanoparticles as photoanode material and reports carrier