CC BY
16
the changes in the proportion of solid waste and sludge, and the degree of decomposition of waste.
In fig. 2 we see the increased percentage of the basic chemical elements, phosphorus, nitrogen and potassium in the obtained organic-mineral fertilizers. This changes the percentage of solid waste and sludge at a constant amount of waste nitric acid. During the experiments, get steady indicators. As a result, it can be argued that the investigated process of obtaining organic-mineral fertilizer from solid waste and sludge is an efficient technological process (S. Sakmanli, M. Alosmanov, H. Bafadarova, 2010).
Conclusion
The organic fertilizer obtained in the process as the desired product and its usage shows the high importance in terms of economic efficiency of the work done. Additionally, all the prerequisites for creating a waste-free process are formed. Even the evolved gases in the
process are captured and absorbed, thus also get a valuable product.
As a result of this research, it has been achieved an acceleration of the process of decomposition of municipal solid waste and sludge generated from waste water, usage of waste nitric acid, obtaining organic — mineral fertilizer with a relatively high content of nitrogen, phosphorus and potassium, preventing of contamination of waste and sludge.
The Government of our country making major steps towards the rapid development of agriculture accepted many programs, laws, etc. in this area. Keeping the above principles the least use of natural resources and the maximum protection of the environment, the proposed technology allow to solve the problem of effective agricultural development and environmental protection. In order to improve this technological process researches continue.
References:
1. Kuzmenkova A. Using composts from municipal solid waste. - Moscow: Rosselhozizdat, 1976.
2. Kazyanova E. The damage caused by of environmental contamination. - Astrahan: Report, 2003.
3. [Electronic resource]. - Available from: http://portaleco.ru/ekologija-goroda/sostav-svojstva-i-obem-tverdyh-bytovyh-othodov.html (2016, 01).
4. Alosmanov M. Physical and chemical research and development of technology of phosphate fertilizers by using industrial wast and natural resources of the South Caucasus. - Baku: ANSA, 1988.
5. Golubets M. Actual matters of environment. - Kiev: Nauka, 1982.
6. Rogojina N. In search of answers to the environmental challenge. World economy and international relations. - 1999.
7. Sakmanli S. Patent No. i20150041. - Azerbaijan, 2015.
8. Sakmanli S., Alosmanov M., Bafadarova H. Physico-chemical research ofprocessing ofmunicipal solid wastes// Ecoenergetika. - 2010. - № 3.
DOI: http://dx.doi.org/10.20534/AJT-17-1.2-83-88
Salimova Nigar A., Professor and associate Professor Mamedova Farida M., Department of Oil-chemical Technologies and Industrial Ecology, Azerbaijan State University of Oil and Industry, Baku, Azerbaijan E-mail: [email protected]
Removal of aromatic hydrocarbons from waste water of industrial oil processing
Abstract: Discharging waste water in marine environment without previous treatment has severe effects on the marine environment and produces aqua-toxicological effects, which is deleterious to aquatic life. The main contributors to acute toxicity of waste water have been found to be the aromatic and phenol fractions
of the dissolved hydrocarbons. Phenol is toxic to fish at a level of 0.05 mg/l, therefore the detoxification of phenols from waste water is of great importance. The aim of this research is studying the effect of treating aqueous solutions containing high concentrations of phenol, 8 mM phenol and low concentration of phenol, 1 m. mole phenol with the enzyme peroxidase extracted from horseradish. Hydrogen peroxide (H2O2) and poly ethylene glycol (PEG), It was found that the most effective addition of' horseradish peroxidase and hydrogen peroxide was l U/mi and 10.0 m. mole respectively at neutral pH, for removing 70 % of the phenol from aqueous solutions containing 8 mM. phenol. It was also found that the most effective addition ofhorseradish peroxidase and hydrogen peroxide were 0.3 u/ml and 3.0 m. mole respectively at neutral pH, for removing 80 % of the phenol from aqueous solutions containing 1m. mole phenol. Precipitation of the phenolic oxidation products resulted from the enzymatic treatment. Through coagulation and precipitation by different coagulants, alumina and quick lime have been studied.
Keywords: Peroxidase, Enzymatic treatment, Phenolic polymers, Coagulation.
Introduction
Phenols in our environment come from various sources. For example, many are found in the waste waters of industries such as petroleum refineries, glue and resin manufacturers, coal processing, pulp and paper mills, and from the leaching of municipal landfills. Phenol is toxic to fish at a level of 0.05 mg/l, therefore the removing of phenols from waste water is of great importance. Most of the methods used for transformation of wastes and pollutants and treating wastewaters are physical, chemical or biological. Chemical transformations involve the application of reagents and reaction conditions to transform and treat target species.
Chemical methods involve the application of reagents and reaction conditions to transform and treat target species. Chemical processes often require the presence of excess quantities of reagents to accomplish the transformation to the desired extent. In addition harsh conditions (e. g., high temperature or extreme of pH) are sometimes required to facilitate the chemical transformation. Many chemical treatment processes are not highly selective in terms of the type of pollutants that are transformed during treatment. The high cost and disposal of contaminated media are the disadvantages of chemical treatment.
Biological processes make use of the natural metabolism of cells to accomplish the transformation or production of chemical species. The metabolic processes occur as a result of a sequence of reactions conducted inside the cell that are catalyzed by proteins called enzymes. Biological processes can often be conducted without the harsh conditions that are necessary during chemical transformations. Due to the large water hold-up volume and bacterial culture contact time, these systems are very large and heavy, and therefore only suitable offshore for low volume application. Also there are operational and
bacterial inhibition problems. The method is best suited to onshore installations where space and volume are not limitations [1].
The following potential advantages of an enzymatic treatment over conventional biological treatment were noted [2]; action on, or in the presence of, many substances which are toxic to bacteria; operation at both high and low concentrations: no shock loading effects: no delays associated with acclimatization of biomass; reduction in sludge volume (no biomass generation). The aims of this study were: extracting the enzyme peroxidase from horseradish roots by mixing with tap water, determining the optimum parameters of enzymatic treatment (Horseradish peroxidase dose, peroxide dose (H2O2)) for oxidation of phenol at aqueous solutions contains high and low phenol concentrations. To remove the phenolic oxidation products by coagulation and precipitation by different coagulants alum and quick lime (CaO).
Methods
H8P enzyme (EC 1.11.1.7) was extracted from horseradish in our lab. All the following chemicals were of analytical grade and were purchased from FECTON (Russian). Hydrogen peroxide (30 % w/v), solid phenol, 4-aminoantipyrine and potassium ferricyanide [K3Fe (CN)61 for analysis of phenol and activity of horseradish peroxidase. Quick lime (CaO) and alum (aluminum sulphate) were used as coagulants.
The horseradish peroxidase enzyme concentration and activity was determined by colorimetric assay [3]. The concentrations of total phenols were measured using a colorimetric method [4].
Batch experiments for enzymatic treatment were conducted at room temperature (approximately 25 °C). The batch reactors were glass vials of capacity 100 mL, which contained 50 ml. of synthetic waste water (phenol — distilled water) and predetermined doses of each
ofhorseradish peroxidase enzyme (HRP), hydrogen peroxide (H2O2) and poly ethylene glycol (PEG) has been added. A magnetic stirrer with a magnetic bar was used for mixing agitation of the synthetic waste water with the reactants for a specific time and at medium speed. After treatment the resulting solution was centrifuged for 30 minutes at 6 000 rpm. The supernatant was analyzed for phenol as described earlier.
For coagulation studies, jar tests were carried out. The objective of the jar test was to determine the optimum dose and the pH value at which a coagulant should be introduced to the waste water. Alum and quick lime were used as coagulants. After treatment of phenol with horseradish peroxidase HRP, H2O2 and PEG, the resulting solution contains colored products (phenolic polymers). Four samples of this solution were treated by a specific dose of alum in a jar test. Each sample of this solution has a 50 ml. volume, alum was added with a specific dose, and stirring occurred for 15 minutes and then stopped. The change in the color of the solution sample (clarification percentage) was measured at a specific time by measuring the relative absorbance of the solution sample at 400 nm. by a photoelectrocolorimeter.
Results and discussions
Extraction of horseradish peroxidase enzyme from minced horseradish roots using soft tap water occurred in a mixer at high speed for a specific time (1-4 hours). Two different ratios of horseradish to tap water were used 50 gram minced horseradish roots to 500 milliliter of tap water, and 100 gram minced horseradish roots to 500 milliliter of tap water. The resulting solution from mixing horseradish with water, for predetermined time, was filtered and the supernatant was centrifuged at 4 000 rev/min. The supernatant was stored at -4 °C. Every day the activity of HRP was analyzed before using the enzyme in the tests. The activity of the enzyme is defined in units, one unit of activity (U) is defined as the number of micromoles of hydrogen peroxide which are consumed in one minute at pH 7.4 and 25 °C [3].
Fig. 1 demonstrates the dependence of the activity of peroxidase on the extraction time. The parameters that were studied were horseradish roots weight to water ratio and time of extraction of enzyme. The activity of enzyme per milliliter extract was dependent on the ratio of horseradish roots weight to water, and the time of mixing the horseradish in tap water.
With increasing the time of mixing, the activity of the enzyme in the extract becomes higher, and reached 7 U/ml for ratio of horseradish roots (HR) to water equal 0.1 (50 gram HR per 500 ml. water), and 8 U/ml
for ratio of HR to water equal 0.2 (100 gram HR per 500 ml. water). The total units of enzyme extracted were dependent on the volume of the water used for extraction. This means that the optimum ratio of HR to water was 0.1 (50 gram per 500 milliliter water) and also the optimum activity of HRP was 7 U/ml extract.
Horseradish peroxidase undergoes a cyclic reaction when reacting with phenolic substrates [5]. This sequence is summarized in the following reactions:
E + H2O2 => Ei + H2O; (1)
Ei + PhOH' => Eii + PhO; (2)
Eii + PhOH" => E + PhO + H2O. (3)
The enzyme starts in its native form (E) and is oxidized by hydrogen penoxide (H2O2) to form an active intermediate compound known as compound I (Ei). Compound I oxidizes one molecule of phenol (PhOH) to form a phenol free radical (PhO) and become compound II (Eii). Compound II oxidizes a second phenol molecule to produce another phenol free radical and complete the cycle by returning to its native form E. The free radicals polymerize and form insoluble compounds which precipitate from solution.
The polymerization reaction is illustrated in equation 4:
PhO + PhO => Polymer of aromatic products. (4) The pH of each sample was adjusted to be between pH 2 and pH 10 using concentrated HCl or NaOH. The pH of the solution was adjusted before stirring and after addition of the phenol, PEG, H202, and HRP. Stirring of the aqueous solution in the presence of the chemical substances has been conducted in the sake of oxidation of phenol by using H2O2 in the presence of HRP enzyme. As a result of oxidation of phenol and formation of the oxidation products (phenolic polymers), which with less toxicity to the environment, the remaining phenol in the reaction solution was decreased and a measurement of the removal percentage of phenol has been achieved.
o 0 -4-,-,-,-,-,-,-
1 1,5 2 3 3,5
Time of Extraction of Peroxidase, hours
Fig. 1. The dependence of the activity of peroxidase on the mixing time of horseradish roots in water
Fig. 2. Effect of pH on the removal of phenol using crude HDP. Experiment conditions: 50 ml. aqueous solution (distilled water) contains 8 mM. phenol, 8 mM. H2O2, 0.8 U/ml HPR, 250 mg/l PEG, and mixing time 3 hours
Fig. 3. Effect of H2O2 additions on remaining phenol in synthetic waste water. Experiment conditions: 50 ml. aqueous solution contains 1.0 mM. (94 mg/l) phenol, 0.2 U/ml HPR, 250 mg/l PEG, and mixing time 3 hours
Fig. 4. Effect of H2O2 additions on remaining phenol in synthetic waste water. Experiment conditions: 50 ml. aqueous solution contains 8 mM.
(752 mg/l) phenol, 1 U/ml HPR, 250 mg/l PEG, and mixing time 3 hours, without addition of PEG
Fig. 2 shows that the optimal removal of phenol from the aqueous solution occurred between pH 4 and 8, with optimum removal percentage 60 % of phenol (Final phenol concentration 3.2 m. mole). The removal of phenol decreased at high acidic and alkaline conditions, this may
be due to the effect of OH and H ions on the oxidation reaction of phenol by using H2O2 and HRP. This study demonstrated that HRP is slightly less susceptible to pH changes and is probably suitable for the treatment of phenol at slightly acidic and alkaline conditions.
Two different phenol concentrations 1 mM. (94 m g/l) and 8 mM. were used in these tests. Hydrogen peroxide (H2O2) was added in predetermined amounts in order to determine the effect of hydrogen peroxide on extent the removal of phenol at initial phenol concentration 1 mM. or 8 mM.
Fig. 3 shows that, at initial phenol concentration 1 m. mole (94 mg/l), as H2O2 dose increases the removal efficiency of phenol increased until the optimum value was attained. Maximal removal of phenol was 70 % in the presence of 3 mM. H2O2. The optimum peroxide concentration H2O2 is a function of the treated phenol concentration and the reaction conditions (HRP dose, pH). The increase of H2O2 dose leads to increase of the removal of phenol.
Fig. 4 shows that, at initial phenol concentration 8.0 m. mole (752 mg/l), as H2O2 dose increases the removal efficiency of phenol increased until the optimum value was attained. The optimum hydrogen peroxide dose was 10 mM. Maximal removal of phenol was 65 % in the presence of 10 mM. H202. A final phenol concentration 2.4 mM, when the initial phenol concentration was 8 mM. and optimum H2O2 concentration was 10 mM.
Two different phenol concentrations 1 mM. and 8 mM. were used in these tests. Peroxidase was added in predetermined amounts in order to determine the effect of HRP dose on extent the removal of phenol at initial phenol concentration 1 mM. or 8 mM. The optimum HRP dose was determined at 1mM. phenol and 3 mM. H2O2 concentration.
As appeared at fig. 5, when the initial phenol concentration was 1 mM, the effective HRP dose was 0.3 u/ml of the solution at H2O2 dose 3 mM, and the PEG dose 250 mg/L. Fig. 5 shows that with the increase in HRP dose, the removal of phenol increases and that maximal removal of phenol were 80 %, at optimum HRP dose 0.3 U/ml and a final phenol concentration 0.2 mM.
As appeared at fig. 6, the optimum HRP dose was determined when the initial phenol concentration was 8 mM, the effective HRP dose was 0.8 u/ml of the solution at H2O2 dose was 8 mM. and PEG dose 250 mg/L. With the increase in HRP dose, the removal of phenol increases and that maximal removal of phenol was 70 %, at optimum HRP dose 1.0 U/ml and a final phenol concentration 2.4 m. mole.
Poly ethylene glycol was prepared in a concentration of 5g/l, and stored in the refrigerator. A predetermined dose was added to each test to determine the effect of PEG on the enzymatic treatment efficiency.
Fig. 7 demonstrates the effect of poly ethylene glycol on the concentration of remained phenol in aqueous solution, when the initial phenol concentration was 8 mM. The effective PEG dose was 275 mg/L, when HRP dose was 1.0 U/ml of the solution and H2O2 dose was 10 mM. Fig. 7 shows that with the increase in PEG dose, the removal of phenol increases and that maximal removal of phenol were 75 %, at optimum HRP dose 1.0 U/ml and a final phenol concentration 2 m. mole.
Alum (aluminum sulphate) was used at two pH values, at slightly acidic conditions pH 5.6 and at slightly alkaline conditions, pH 8.0. Fig. 8 shows that at slightly alkaline conditions, pH 8.0, the coagulation of the colored products was little by alum. Maximum color removal of the colored products (clarification percentage) was only 40 %, at an alum dose 5.5 gm/I, after 18 hours (clarification time) from the moment of stopping the stirring in the jar test. Also figure 8 illustrates that when using alum at slightly acidic conditions, pH 5.6, the coagulation of the colored products were increased by increasing the alum dose and clarification time (time after the stopping the stirring). Maximum color removal of the colored products was only 5Q%, at an alum dose 3.0 gm/I, and after 3 hours, and increased to become 84 % at the same dose and after time18 hours from the moment of stopping the stirring in the jar test.
Lime (CaO) is used for color removal (precipitation of color products by lime) from pulping and bleaching effluents [6]. Molecular weight of color products is one of the major factors influencing the precipitation of color products. Pulping and bleaching effluents was treated by horseradish peroxidase and H2O2 and found that the colored products from this treatment have high molecular weights greater than 5000. They found that lime can almost completely remove color products with molecular weights greater than 5000. This previous work was encouraging us to demonstrate the capability of lime to precipitate the color products resulting from oxidation of phenols by HRP and H2O2 in the presence of poly ethylene glycol.
Fig. 9 shows that as the addition of lime increases the pH of solution becomes above pH 10.5, and causes fast precipitation of the colored products. Maximum color removal (clarification) of the colored products was 60 %, at a lime dose 3 gm/l, after 30 minutes from the moment of stopping the stirring in the jar test (clarification time). The
percentage of color removal increases with the increase of the clarification time (after moment of stopping the stirring) in the jar test. Maximum clarification of the colored products was 85 %, at a lime dose 3 gm/l, after two hours. Fig. 9 shows fast and high efficiency of color removal using lime, as the lime doses increase and as the time after moment of stopping the stirring increases as well.
Fig. 5. Effect of additions of HPR on the phenol remaining in synthetic waste water, at initial phenol concentration, 1 m. mole. Experiment conditions: 50 ml. aqueous solution contains 1.0 mM. (94 mg/l) phenol, 3.0 mM. H2O2, 250 mg/l PEG, and mixing time 3 hours
Fig. 6. Effect of additions of HPR on the phenol
remaining in synthetic waste water, at initial phenol concentration, 8.0 m. mole. Experiment conditions: 50 ml. aqueous solution contains 8 mM. (752 mg/l) phenol, 8 mM. H2O2, 250 mg/l PEG, and mixing time 3 hours
Fig. 7. Effect of polyethylene glycol dose on the remaining phenol conc. in aqueous solution after enzymatic treatment, when the initial phenol concentration was 8.0 m. mole. Experiment conditions: 50 ml. aqueous solution (distilled water contains 8 mM. (752 mg/l) phenol), 1 U/ml HRP, 10 mM. H2O2, and mixing time 3 hours
0 1 2 3 4 5 6
Alum Dose, gm/1
Fig. 8. Effect of alum addition on color removal (coagulation) of phenol polymers, at different pH values
100
c_> o —--
12 3 4
Quick Lime, gm/L
Fig. 9. Effect of coagulation with quick lime for phenolic polymers resulting from enzymatic treatment of phenol
Conclusions
This study has determined the possibility of treating synthetic waste water (distilled water contains both high amounts of phenol, 8 mM, and a low amount of phenol 1.0 mM) by the enzymatic system (HRP-Peroxide). The optimum parameters of enzymatic treatment of synthetic waste water containing 1 mM. initial phenol concentration were at pH 7.0, 0.3 U/ml HRPdose, 3.0 mM. H2O2 dose and PEG 275 mg/l achieved a final phenol concentration 0.2 mM. with a removal percentage of water contain 8 m. mole phenol were at pH 7.0, 1 U/ml HRP dose, 10.0 mM. H2O2 dose and PEG 275 mg/l achieved a final phenol concentration 2.0 mM. with a removal percentage of phenol 75 %. The optimum coagulant was quick lime used for precipitation of colored oxidation products of phenol and 85 % clarification could be attained after 2 hours.
Compliance with ethical standards
• Disclosure of potential conflicts of interest — there is not conflict of interest.
• Research involving Human Participants and/or Animals: For this type of study formal consent is not required.
• Informed consent: Informed consent was obtained from all individual participants included in the study.
References:
1. International association of oil and gas producers (I. A.O. G.P.) Aromatics in produced water: occurrence, fate and effects and treatments. - IAOGP, January 2002. - Report No. 1, 20/324.
2. Nicell J. A., Al-Kassim L., Bewtra J. K. and Taylor K. E. Treatment of waste waters by enzyme catalyzed polymerization and precipitation//Biodeterioration Abstracts. - 1993. - № 7(1). - P. 1-8.
3. Wright H. Characterization of soybean peroxidase for the treatment of pheniloc waste water, Master of Engineering Thesis. - McGill University, Montreal, Canada, 1995.
4. Yiseon Han. Arthromyces ramosus peroxidase catalyzed phenol removal, Master of Engineering Thesis. - University of Alberta, Edmonton, Alberta, 1998.
5. Klibanov A. M., Alberti B. N., Mon-is E. D. and Felshin L. M. Enzymatic removal of toxic phenols and anilines from wastewaters//J. Applied Biochem. - 1980. - Vol. 2. - P. 414-421.
6. Schmidt R. L., Joyce T. W. An enzymatic pretreatment to enhance the lime precipitability of Pulp. Mill Efflu-ents//Tappi. - 1980. - Vol. 63. - P. 63.
Preparation of surfactants reducing the viscosity of heavy oil from raw fatty acid of cotton soap stock
D OI: http://dx.doi.org/10.20534/AJT-17-1.2-89-92
Nabiyev Akramjon Botijonovich, Abdurahimov S. A., Namangan State University, Tashkent Institute of Chemical Technology E-mail: [email protected]
Preparation of surfactants reducing the viscosity of heavy oil from raw fatty acid of cotton soap stock
Abstract: This paper studied the effective viscosity of the local oil at a constant voltage shifts evaluate the effectiveness of synthetic surfactant to reduce the viscosity of the local oil. Studies for obtaining surfactants reducing the viscosity of the oil from the raw fatty acid of cotton soapstock (CS) show that a rational scheme was selected for gaining of surfactants from raw fatty acid of cotton soap stock in the form of higher fatty alcohols and their modification methods sorbitan or sulfation.
Keywords: oil, viscosity, sulfate, paraffin, gossypol, lecithin, cephalin.
Specific feature of oil from the Jarkurgan (Sur- Today, promising is the use of depressant i. e. surface-
khandarya region) and Mingbulak (Namangan region) fields in Uzbekistan is the high content ofparaffin, resins, asphaltenes of mineral salts and other related hydrocarbon components that significantly increase their viscosity and reduce their flow through the pipeline.
It is known that the high viscosity of the oil, not only complicates the process of its production from the wells, but also its industrial processing, which has a negative impact on their technical and economic indicators. To address these shortcomings in practice (especially in autumn and winter) the pipelines should be heated with steam where oil transport distance exceeds 10-15 km. The use of solvents for diluting high-viscosity oil is not desirable because it is related to fire safety oil explosion [1].
With in-plant transport of high-viscosity oil for less (less than 5 km.) distance it is effectively to use their electromagnetic processing (including microwaves), which, along with a decrease in viscosity of the oil increases its turnover and significantly reduces the deposition of waxes, resins and mineral salts in the pipes [2]. In this case, the problem of explosion, fire of oil pipelines requires their own individual solutions tailored to their construction.
It was offered the methods of application of ultrasonic cavitation and mechanical-chemical activation (MCA) on lowering the viscosity of oils of different composition [3].
Unfortunately, the influence of mechanical stress on the decrease in viscosity of the oil is not a long time and should therefore be used repeatedly, which significantly overstates their energy costs for transportation by pipeline.
active agents (surfactants), and reduce the oil viscosity increase their fluidity in a pipeline.
It is known that the surfactants have the ability to lower surface tension in the interphase layer, as they dissolve selectively in one of the phases, the dispersion medium to be concentrated at the interface and there form an adsorption layer as a film. Reduced surface tension increases with the fineness of the disperse phase [4].
Mainly characterized by the oil viscosity, density, dispersion, electrical properties and stability of aggregate. Their viscosity usually varies within wide limits and depends on the intrinsic viscosity of the oil, the temperature and so on. They being dispersed systems have abnormal properties that under certain conditions are non-Newtonian fluids and characterized by an apparent (effective) viscosity [5].
We investigated on viscometer VPN-01 at a constant shear stress the effective viscosity of the local oil. This shear stress of test oil sample was calculated by the following formula [5]:
T = ass (1)
where: k — the coefficient, which is equal to 0.63 Pa/V to 100 mm. gauge and 43 Pa/V to 20 mm. gauge;
U — stress in volts.
The shear rate was determined by the formula:
Y=A/T, (2)
where: A — a constant measuring unit; T — Period of rotation, determined by the frequency indication.
Hence, the effective viscosity of the oil is determined by the formula [5]:
n = T .a/!. (3)
