Open Access Original Research Article

Investigation of the Process of Purification of Wet-Process Phosphoric Acid and Production of Concentrated Phosphoric Fertilizers Based on it

Gulnoza Kodirova, Israiljon Shamshidinov, Boxodir Sultonov, Rikxsitilla Najmiddinov, Bakhodir Mamurov

Chemical Science International Journal, Page 1-10
DOI: 10.9734/CSJI/2021/v30i130209

Fluoride compounds have the most harmful effects on the environment. The main source of fluoride in the soil is phosphorus-containing fertilizers. Purification of wet-process phosphoric acid (WPPA) from fluorine will significantly reduce its content in phosphorous-containing fertilizers and improve the quality of the resulting products. The aim of the study is to reduce the content of fluorine and sulfates in the wet-process phosphoric acid by introducing calcium carbonate, dolomite or phosphorite into the finished extraction pulp before filtration and obtaining high-quality calcium and magnesium-containing phosphate fertilizers based on it. Phosphates were determined by differential photometric, fluorine – ionometric, calcium, magnesium, aluminum, and iron-complexometric, and sulfates-by weight methods. For the first time, scientifically-based data were obtained on the simultaneous reduction of the content of fluorine and sulfates in WPPA from phosphorites of Central Kyzylkum and the production of calcium-magnesium phosphate fertilizers based on it. Optimal technological parameters of the process of simultaneous defluorination and desulfatation of  WPPA from Central Kyzylkum phosphorites with calcium carbonate, dolomite and washed burnt phosphoconcentrate (WСPC) were found by introducing them into the second section of the extractor, into the finished extraction pulp in the amount of 100% for sulfate binding and 100-150% for fluorine binding, as well as obtaining high-quality products based on purified WPPA. The degree of transition of fluorine to the gas phase and phosphogypsum at a rate of 100-150% of calcium oxide for fluorine binding is 86.2-89.4% and its content in the wet-process phosphoric acid decreases from 1.18% to 0.22-0.29%. At the same time, the SO3 content in the acid decreases from 1.21% to 0.24-0.26%. The filtration rate of the sulfate-phosphate pulp varies slightly and is 807.6-812.6 kg/m2·h by dry residue.

Open Access Original Research Article

Kunyima Method Validity in Sesame Seeds Oil Extraction "Democratic Republic of Congo"

A. B. Kunyima, H. M. Kaseya, S. N. Lusamba, C. K. Mulaji, B. M. Ataweza

Chemical Science International Journal, Page 11-17
DOI: 10.9734/CSJI/2021/v30i130210

Background: The very rich vegetable patrimony of Democratic Republic of Congo (DRC) demands a local abundant production of its fruits, roots and seeds by means of appropriate technology to relieve somewhat the problem of population health because indeed those fruits, seeds, roots and leaves are reputed to have very excellent virtues in various fields such as medicine, pharmacology, cosmetic products, food and so forth. Prior to this work papers have been published on Gourd seeds oil and Moringa seeds oil extractions in order to size a continuous stirrer pilot tank of extraction. KUNYIMA method has been successfully used and is still successfully used in this present article concerning sesame (Sesamum indicum L.) seeds oil extraction in dilute medium.

Aim and Objective: In this paper it can be seen the reasoning leading to KUNYIMA method is relevant and can be used to size commercial tank giving thus home rational technology.

Methodology:  The Soxhlet extraction of oil from sesame (Sesamum indicum L.) seeds has been performed in dilute medium using petroleum ether as solvent.

Results:  The obtained results are satisfactory and are perfectly in agreement with the proposed model. Commercial tank construction on rational calculation is now possible.

Conclusion: KUNYIMA method once more is valid and allows to calculate the sizing factor needful to determine the reactor optimal volume.

Open Access Original Research Article

Physico-Mechanical Properties of Composites Produced from Thermoplastic Polymers Filled with Egg Shell

Helen Obianuju Ofor

Chemical Science International Journal, Page 28-45
DOI: 10.9734/CSJI/2021/v30i130212

The aim of this research is to develop environmentally friendly, lightweight composites using egg shell, as filler in some thermoplastic polymer matrices Polypropylene (PP), High Density Polyethylene (HDPE), Acrylonitrile-Butadiene-Styrene (ABS) and Polystyrene (PS) polymer; to determine the physico-mechanical properties of the egg shell agro-residue polymer composite, to find if there is any new improvement over the properties of the starting thermoplastic polymer composites.This research work studied the reinforcement potential of egg shell in thermoplastic polymers (HDPE, PS, PP and ABS). Egg shell was collected from the surroundings of Ekwulumili in Nnewi-South L.G.A of Anambra State, Eastern Nigeria where they have been dumped after usage. The research was carried-out at JUNENG NIG LIMITED Enugu, Civil Engineering Department Laboratory University of Nigeria and Chemical Engineering Department Laboratory Ahmadu Bello University (ABU), Nigeria; between May 2016 and August 2018. The agro-wastes were grand into power and incorporated into the virgin thermoplastic polymers as filler at varied levels of 3%, 6%, 9%, 12% and 15%. The virgin thermoplastic polymers were used as the Control in the study. The mechanical properties of the composites produced were determined using American standard for Testing and Materials (ASTM), Standard Testing Methods. The results generally showed significant improvements in the physico-mechanical properties of the egg shell filler composites which were largely influence by the amount of filler in the composites. However, the water absorption capacities of the composites were found to be higher than those of the virgin thermoplastic polymers; an indication that egg shell reinforced at different percentage values are not compactable with polymer matrices due to the hydrophilic nature of natural fibers. HDPE at 15% (8.95%), 3% (4.28%), 9% (3.11%), 12% (0.88%) and 6% (0.85%) and Control (0.00%). PS, at 3% (8.24%), 6% (7.49%), 12% (2.18%), 9% (1.13%), 15% (0.49%) and Control (0.12%). PP, 9% (5.02%), 12% (3.99%), 3% (3.06%), 6% (0.78%) and 15% (0.67%) and Control (0.13%). ABS at 6% (5.52%), 12% (5.03%), 15% (1.50%), 3% (1.02%) and 9% (0.83%) respectively also had very high-water absorption than the Control (0.11%).

Brinell hardness property of egg shell/polymer matrix composites had better values than the virgin polymer; HDPE value at 6% (39.48 N/mm2) > 3% (39.46 N/mm2) > 9% = 12% (39.40 N/mm2) > 15% (39.39 N/mm2) and Control (36.44 N/mm2). PS at 3% (39.60 N/mm2) > 6% (39.56 N/mm2) > 9% (39.54 N/mm2) > 12% (39.12 N/mm2) > 15% (38.85 N/mm2) respectively had higher brinell hardness above the Control (37.04 N/mm2). PP had value only at 3% (29.28 N/mm2) that showed lower brinell hardness; 6% (39.35 N/mm2) > 15% (37.55 N/mm2) > 9% (37.36 N/mm2) and > 12% (36.93 N/mm2) respectively showed higher brinell hardness than the Control (36.32N/mm2). ABS; 12% (39.54 N/mm2) > 6% (39.40 Nmm2) > 3% equal to 9% (39.39 N/mm2) and > 15% (39.35 N/mm2) respectively had better brinell hardness than the pure polymer. Abrasion results of all egg shell/polymer matrix composites used (exception of PS) showed poor abrasion values than the Control; For HDPE the value at 3% (29.47 g/s), 9% (25.03 g/s), 12% (23.54 g/s), 15% (23.13 g/s) and 6% (22.36 g/s) and Control (14.57 g/s). PS, at 12% (12.16 g/s), 3% (10.79 g/s), 6% (8.35 g/s),15% (6.69 g/s) and 9% (5.59 g/s) and Control (16.20 g/s). PP had at 12% (55.47 g/s), 6% (47.90 g/s), 3% (40.16 g/s), 9% (32.80 g/s) and 15% (22.11 g/s) and Control (18.02 g/s). ABS at 3% (15.05 g/s), 15% (87.52 g/s), 6% (24.10 g/s), 12% (22.08 g/s), 9% (21.07 g/s) and Control (17.39 g/s).

The impact strengths absorbed higher amount of energy than the Control in PP, HDPE, ABS, 3%, 6%, 9% of PS, 3%, and 6% of PP in egg shell composites. HDPE at 12% (3.12 J/mm2) > 3% (2.95 J/mm2) > 6% (2.88 J/mm2) > 9% (2.35 J/mm2) > 15% (1.63 J/mm2) and Control (1.84 J/mm2). In PS, 3% (4.03 J/mm2) > 6% (2.86 J/mm2) > 9% (2.67 J/mm2) >12% (1.48 J/mm2) > 15% (1.25 J/mm2) and Control (1.98 J/mm2). PP at 6% (2.16 J/mm2) and 3% (1.63 J/mm2) showed higher impact strength while 15% (1.23 J/mm2) > 9% (1.08 J/mm2) > 12% (0.91 J/mm2) respectively showed lower impact strength than the Control. In ABS 15% (1.14 J/mm2) absorb lower energy while 9% (1.17 J/mm2) had equal value with control (1.17 J/mm2); at 12% (3.18 J/mm2), 6% (2.16 J/mm2), and 3% (1.38 J/mm2) respectively absorb higher energy than the Control. This study has provided different combinations of agro-waste/agro-residue thermoplastic polymer composites which has potential application in the automobile and building construction industry.

Open Access Original Research Article

Assessing the Seasonal Changes on Physicochemical Parameters and Major Nutrient Levels in Water and Sediments from Sulal River, Bureti Sub County, Kericho County, Kenya

S. Cherotich, D. A. Abong’o, J. O. Onyatta

Chemical Science International Journal, Page 46-58
DOI: 10.9734/CSJI/2021/v30i130213

Sulal River is a victim of nutrient pollution as it crosses different small-scale tea farms in Bureti Sub County, Kericho County. A study was conducted to evaluate different physicochemical parameters and major chemical fertilizer’s nutrients levels in water and sediments from Sulal River. In order to understand the degree of pollution in the river due to inflow of agricultural chemical fertilizer residue levels from its catchment, the samples were collected in the dry (February 2019) and wet seasons (November 2019). The ten chosen sampling sites stretched a length of 12 Km. Samples were analyzed for pH, dissolved oxygen (DO), total dissolved solids (TDS), electrical conductivity (EC), sediment and water content (WC), nitrate-nitrogen (NO3-N), phosphorous (PO3-P) and potassium (K) using standard methods. Results were analyzed using IBM SPSS 20. The average results during dry and wet seasons in water samples for pH were 6.72±0.05 and 6.38±0.21, DO 6.78±0.59 and 9.58±0.64 mg/L, EC 174±5.02 and 205±20.14 µS /cm, TDS 92±4.59 and 120.70±19.57 mg/L, NO3-N 0.58±0.21 and 1.19±0.22 mg/L, PO3-P 0.00±0.00 and 0.13±0.84 mg/L and K 0.26±0.08 and 0.84±0.19 mg/L respectively. The average results during dry and wet seasons in sediment samples for pH were 6.62±0.20 and 6.75±0.17, EC, 67±6.66 and 52±10.19 µS /cm, WC 16.96±3.95 and 129.84±5.00%, NO3-N 0.70±0.35 and 0.42±0.23 mg/kg, PO3-P 0.49±0.25 and 1.14±0.40 mg/kg and K 1.53±0.45 and 2.86±0.31 mg/kg respectively. The levels of P in water during wet season and in sediments samples in both seasons were however, above the WHO (0.025 mg/L) and KEBS (0.030 mg/L) recommended limit for drinking and domestic use and WASREB (0.005 mg/L) level for the likelihood of eutrophication. Availability of excess phosphorus can accelerate eutrophication. The diversity of cancers has also been associated with drinking water containing phosphorous levels. The water from Sulal River may be used for irrigation purposes but not for drinking and domestic purposes. Significant seasonal variations were observed in all parameters analyzed except NO3-N in sediments. This indicates that rainfall had a great effect on some soil physicochemical properties.

Open Access Review Article

Characterization of the Molecular Lipophilicity of Mycolactones A/B and C, Infectious Factors of Mycobacterium ulcerans Agent of Buruli Ulcer

Kadjo François Kassi, Jean Missa Ehouman, Mamadou Guy-Richard Koné, Lamoussa Ouattara, Georges Stéphane Dembélé, Nahossé Ziao

Chemical Science International Journal, Page 18-27
DOI: 10.9734/CSJI/2021/v30i130211

The work was undertaken as part of the Buruli ulcer control program. It is particularly about the determination of the lipophilicity of mycolactones A/B and C, infectious factors of Mycobacterium ulcerans, the agent of Buruli ulcer. The REKKER method and some free software such as MOLINSPIRATION, ACD/ChemSketch and EPIWED were used for the determination of the lipophilicity of mycolactones A/B and C. Very high logP values were found and respectively ranged from 12.11 to 11.41 for mycolactone A/B and 11.69 to 11.58 for mycolactone C. These values obtained from this coefficient, show that mycolactones A/B and C are naturally lipophilic and that actually reflects their effective presence in the subcutaneous fat of the infected area. These results are very encouraging and promising. They are key factors for a better understanding of the biological activities of the two mycolactones and pave the way for the proposal of a mechanism to annihilate their destructive effects.