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This study aims to evaluate and reuse defective products and cotton wastes resulting from factories producing socks in Bishkek, Kyrgyzstan, in order to solve the issues related to their disposal. For this purpose, microcrystalline cellulose (MCC) was obtained after isolating the cellulose from these wastes by treating them with sulfuric acid solutions. Then, under constant NaOH and monochloroacetic acid (MCA), CMC with the highest DS value of (0.65) was synthesized at 65 degrees C for 2 hours. When the reaction time was increased (3, 4 and 5 hours) at the same temperature, the DS value decreas ...More
Kyrgyzstan is a landlocked country in Central Asia, famous for its crystal-clear lakes, majestic Tien Shan Mountains that bisect the territory of Turkistan, and magnificent natural beauty. This study aims to evaluate the fruit (acorns) of the oak trees (Quercus robur L.) grown in Bishkek, the capital city of Kyrgyzstan. For this purpose, carboxymethyl acorn starch (CMAS), which is not synthesized in literature, is first synthesized by isolating acorn starch (AS) from the acorns. The structures of CMASs are characterized by H-1(C-13)-NMR, FT-IR, XRD, and SEM techniques. The viscosities of the s ...More
Zarlık MAYMEKOV | Canarbek İZAKOV | Nurzat ŞAYKİYEVA | Mustafa DOLAZ | Mehmet KOBYA
Under practical conditions, one of the possible solutions to the problem of treatment of hydrogen-sulfide-containing industrial wastewater is the electrochemical oxidation of sulfides. In this work, the model system Fe-NaCl-Na2S-H2SO4-H2O is considered, an experimental setup is constructed, and the electrocoagulation process is studied in a wide (288-308 K) range of temperatures of an aqueous solution of hydrogen sulfide. The optimal ratios between the initial components in the system are determined. The experimental and calculated pH of the solution are found. The system is thermodynamically ...More
Nurzat ŞAYKİYEVA | Mustafa DOLAZ | Zarlık MAYMEKOV | Mehmet KOBYA
In this study, sulfide removal was carried out in the Electrocoagulation process under controlled and uncontrolled pH conditions. Under optimum conditions, electrocoagulation took place in less than 40 minutes at uncontrolled pH and less than 30 minutes at controlled pH to reduce the sulfite concentration of the effluent below 0.5 mg/L. The reaction rate constant and iron-sulfide molar ratio for sulfide removal were 14.09 x 10(-2) min(-1) and 0.97 mol/mol, respectively; under uncontrolled pH conditions, they were 22.88 x 10(-2) and 0.97 mol/mol at controlled pH. The mg sulfide removed per g Fe ...More
This study aimed at the recovery of cellulose from abundantly available wastes and its sustainable application. Firstly, in the cleaning process, cellulose-containing wastes, such as air particle vacuum powder (APVD), towel clippings (TC), and cottonseed delintation residues (CD), were thoroughly washed, separately, with tap water to remove some organic and inorganic impurities. The cotton slurry was purified by 17.5 NaOH at 90 degrees C for about 4 hours, then filtered and washed with tap water. Afterwards, the resulting pulp was bleached by NaOH and H2O2 , and washed with distilled water unt ...More
Unfortunately, cellulose, which is the most abundant of natural polysaccharides in the world, and is found in high amounts in cotton and the waste/by-products of textile factories, cannot be recycled sufficiently. As an attempt to find a solution to this problem, in this study, a by-product of the towel production process, called towel clippings (TC), was used as a source of cellulose for obtaining HPMC. HPMC was synthesized for the first time from the reaction of cellulose, propylene oxide (PO) and chloromethane (CM) under pressure in a gas-tight laboratory scale reactor and then evaluated as ...More
Electrocoagulation (EC) is a significantly efficient method for As removal from waters and received considerable attention recently. In this study, the natural groundwater (GW) samples containing As concentrations of GW-1: 538.8 mu g L-1, GW-2: 1132.1 mu g L-1, and GW-3: 52, 000 mu g L-1 were obtained from different provinces and treated by EC process using different iron anodes (plate, ball, and scrap). To achieve drinking water As standard (10 mu g L-1), the operational time, applied current, and As removal optimization for all anode types were studied. At applied current of 0.025 A, the As ...More
The surfaces of titanium (Ti-6Al-4V) implants, which are widely preferred as implant material in medicine and dentistry, are biomimetically coated with nanohydroxyapatite (nHAp) in simulated body fluid (10XSBF) with microwave-assisted 10-f time concentration solution. A second layer was formed with different amounts of non-toxic AgNO3 to impart antibacterial properties to the implant materials coated with nHAp. In comparison of uncoated implants with nHAp and Ag-coated Ti-6Al-4V implants, surface morphologies were evaluated by SEM analysis, phase grade and structure were evaluated by XRD, and ...More
Two new Schiff bases ligands (HL1 and HL2) and their Co2, Mn2, Fe3, Ru3, Cr3, and VO2 complexes were synthesized and characterized by FT-IR, 1H-NMR, and Mass spect. and analytical methods. A single-crystal X-ray diffraction study determined the molecular structure of HL1. The catalytic effects of metal complexes on benzyl alcohol and potato starch (PS) oxidation were compared in an H-2O-2 medium. The percent conversion of benzyl alcohol to benzaldehyde and benzoic acid was determined by Gas Chromatography. [Co(L-1)(2)], [Mn(L-1)(2)], [Co(L-2)(2)], and [Mn(L-2)(2)] showed the highest catalytic ...More
The utilization of forest auxiliary products and their conversion into products with higher added value is important for the use of renewable resources. For this purpose, acorns belonging to the Q. coccifera species were collected in November, which is their ripening period, and dried and ground in the laboratory. Then, acorn starch (AS) was isolated from the sieved acorn flour. For 5 g of this isolated AS, hydroxypropyl acorn starch (HPAS) with the highest molar substitution (MS = 0.319) was synthesized by optimizing at 45 degrees C for 5 h with 30 g of propylene oxide and 1.88 g of NaOH. The ...More
According to scientists, keratin is one of the most abundant fibrous materials in nature after cellulose and chitin in the world. Several nature fibrous materials have a wide range of application starting from biomedical application to the construction sector, and especially the textile sector. The uses of natural fibers in these sectors are economical for increasing their specific properties, such as antibacterial properties, flexibility, tensile strength, shear strength, toughness, etc. This paper presented a new type of keratin-chitosan biofilms with the separation of keratin from waste chi ...More
In this study, the treatability of real textile wastewater [dissolved organic carbon (DOC): 500 mg/L), color: 6383 Pt-Co, sulfate: 362 mg/L)] was investigated in sequential anaerobic moving bed bioreactor (AnMBBR) and aerobic membrane bioreactor (AeMBR). AnMBBR was filled with 40 % career material (Kaldnes K1). The effect of different hydraulic retention times (HRTs) (6-48 h) and powdered activated carbon (PAC) addition (1 g/L) was investigated for system optimization. Sequential AnMBBR- AeMBR was successfully operated for textile wastewater treatment corresponding to 92 %, and 90 % dissolved ...More