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1

Green Almond Peels a Promising Biosorbent for Cationic Dyes Removal: Characterization, Effect of Process Parameters and Kinetic Modeling

Bettayeb Souhila, Merakchi Akila, Lounici Hakim

Ecological Engineering & Environmental Technology

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2024

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Vol. 25, iss. 2

351--365

EN

In the present work, almond peels (AP), an inexpensive and widely available cellulosic material in Algeria, have been utilized as an effective natural adsorbent to eliminate methylene blue from water-based solutions. SEM and FTIR analysis were employed to qualify the adsorbent. The effect of particle size, pH of solution, agitating rate and adsorbent dose were optimized to measure the almond peels capacity of adsorption. The pseudo-first and secondorders, Elovich, and intra-particle diffusion models were employed for analyzing adsorption kinetics. Equilibrium adsorption was examined through Langmuir, Freundlich, and Temkin isotherms. The sorption mechanism was most clearly outlined by the pseudo-second-order kinetic and Freundlich isotherm equations. Our experimental findings indicate that the efficacy of employing these porous adsorbents stems not only from their effective performance attributed to their compositional and structural properties but also from their easy separation from solutions owing to their macroscopic dimensions.

2

Peganum Harmala L. plant as green non-toxic adsorbent for iron removal from water

Alsaiari Raiedhah, Shedaiwa Iman, Al-Quadri Fatima, Musa Esraa E., Alqahtani Huda, Alkorbi Faeza, Alsaiari Norah A., Mohamed Mervate M.

Archives of Environmental Protection

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2024

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Vol. 50, no 1

3--12

EN

The present work focuses on examining the batch removal of Fe (III) from water using powdered Peganum Harmala seeds, characterized as FT-IR. In this work, several parameters are measured, including contact time, pH, Fe (III) concentration, reaction temperature effect, and adsorbent dose effect. Fe (III) adsorption was assessed using a UV-vis spectrophotometer at a wavelength of 620 nm. The findings demonstrated a positive correlation between the dosage of adsorbent and Fe (III) ions removal, with an increase in the adsorbent dose corresponding to higher elimination of Fe (III) ions. Therefore, the Langmuir isotherm model yielded more accurate equilibrium data compared to the Frendulich model. The kinetic data were mostly analyzed using a pseudo-second-order model rather than a pseudo-first-order model. Thermodynamic parameters, including enthalpy (ΔH◦), entropy (ΔS◦), and free energy (ΔG◦), were calculated. The adsorption process was found to be exothermic. Overall, Peganum Harmala was a favorable adsorbent for removing Fe (III) from aqueous solutions.

3

Implementation of solidified carbon dioxide to anaerobic co-digestion of municipal sewage sludge and orange peel waste

Szaja Aleksandra, Bartkowska Izabela

Archives of Environmental Protection

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2024

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Vol. 50, no 1

72--79

PL

W przeprowadzonych badaniach zaproponowano zastosowanie niskotemperaturowej obróbki wstępnej z wykorzystaniem zestalonego ditlenku węgla (SCO2 ) w celu przezwyciężenia trudności związanych z dwuskładnikową fermentacją odpadów odpadów cytrusowych (OPW) i komunalnych osadów ściekowych (SS). Przeprowadzono dwa eksperymenty, w pierwszym zbadano wpływ zastosowania SCO2 na właściwości mieszaniny OPW i SS. W drugim przeprowadzono fermentację mezofilową w układzie porcjowym. Uzyskane wyniki wykazały, że zastosowanie SCO2 spowodowało wzrost zawartości rozpuszczonej materii organicznej wyrażonej jako sChZT i DOC oraz spadek zawartości limonenu. Uzyskany korzystny efekt w obecności SCO2 spowodował poprawę produkcji zarówno biogazu, jak i metanu. W tym przypadku uzyskano również korzystny wpływ na kinetykę produkcji metanu. Wydajność produkcji biogazu i metanu wyniosła odpowiednio 576±17,8 i 358±19,1 mL/ g smo. Z kolei, w reaktorze kontrolnym, w którym przeprowadzono fermentację osadów ściekowych wskaźniki te osiągnęły wartości odpowiednio 496±11,4 i 317±13,4 mL/ g smo. Dodatkowo, w przypadku zastosowania SCO2 uzyskano wyższy stopień przefermentowania oraz stabilny przebieg procesu. Z kolei, w przypadku fermentacji dwuskładnikowej OPW i SS nie poddanej wstępnej obróbce w porównaniu do próby kontrolnej odnotowano zmniejszoną produkcję metanu oraz negatywny wpływ na stabilność procesu. Zaproponowana niskotemperaturowa obróbka wstępna z wykorzystaniem zestalonego ditlenku węgla stanowi przełom w badaniach w zakresie zastosowania odpadów cytrusów w procesach beztlenowych, umożliwiając ich efektywne zagospodarowanie z produkcją energii.

4

Kinetic of Oil Sludge Thermolysis Process in Presence of Nickel, Cobalt and Iron-Supported Microsilicate

Tyanakh Sairagul, Baikenov Murzabek, Yun Ma Feng, Khamitova Tolkyn, Balpanova Nazerke, Tulebayeva Balzhan, Kyzkenova Aikorkem, Karimova Aliya, Rakhimzhanova N.Z., Kochegina E.V.

Polish Journal of Chemical Technology

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2023

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Vol. 25, nr 3

101--109

EN

The article is devoted to the experimental determination of thermokinetic parameters of oil sludge thermal degradation using the model-free Ozawa-Flynn-Wall method in the presence of a nanocatalyst (nickel, cobalt and iron-supported microsilicate) by calculating Arrhenius kinetic parameters (activation energy and pre-exponential factor). The phase composition of the reflex microsilicate was established – 4.12; 2.51 Å – SiO2, nickel-supported microsilicate reflexes: 2.09; 1.48 Å – NiO, reflexes: 4.25 Å – SiO2 and acid numbers of microsilicate – 64 μmol/g of prepared nanocatalysts. Using the method of Brunauer, Emmett and Teller, the specific surface area of the microsilicate was established – 18.3 ± 0.3 m2 /g, the microsilicate with nickel applied – 20.9 ± 0.2 m2 /g and the adsorption isotherm of the prepared nanocatalysts (microsilicate with nickel, cobalt and iron). Thermokinetic parameters of thermal decomposition of oil sludge without a catalyst and with a catalyst at an increment of 0.9 are 99.0 and 93.3 kJ/mol nickel-supported microsilicate, 51.9 kJ/mol cobalt-supported microsilicate, 111.3 kJ/mol iron-supported microsilicate and non-metal-supported microsilicate 173.7 kJ/mol, respectively. The study of the kinetic parameters of pyrolysis of oil sludge using various catalysts makes it possible to assess their influence on the process of decomposition of organic components. The results of the experiments showed that the use of catalysts significantly affects the destruction of oil sludge. Dynamic thermal analysis at different heating rates studied the dynamics of oil sludge decomposition. The study of the effect of catalysts on the kinetic parameters of oil sludge pyrolysis is an important step in the development of new methods for the disposal of petroleum products and the reduction of their negative impact on the environment. The obtained experimental data on thermal degradation kinetics of oil sludge will find application in designing a reactor for the process of destructive hydrogenation of heavy hydrocarbon raw materials.

5

Kinetics of simultaneous recovering of Au and Ag from CTs by chloridizing volatilization methods

Weiwei Wang, Zhengyao Li, Shanshan Yang, Kai Ma, Xin Gao, Shaoqi Han, Shaochun Hou, Hecheng Miao

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 6

art. no. 172522

EN

Cyanide Tailings (CTs) are known as hazardous resources that accumulate hundreds of millions of tons, threatening the ecological environment. This work proposes an eco-friendly and efficient way to recover gold and silver from CTs. The effects of calcium chloride dosage, silicon dioxide dosage, pellet moisture content, roasting temperature, and roasting time on Au and Ag chloridizing volatilization were studied. The kinetics of simultaneously recovering of gold and silver from cyanide Tailings by chlorination roasting was investigated. It was determined that the chloridizing volatilization rates increased with increasing calcium chloride dosage, temperature and decreasing silicon dioxide dosage, pellet moisture content. The chloridizing volatilization kinetics followed a shrinking core model, with inter-diffusion through gangue layer as the rate determining step. This finding is in accordance with the apparent activation energy (Ea) of 24.01 kJ•mol-1 (Au) and 24.62 kJ•mol-1 (Ag). The orders of reaction with respect to moisture content, temperature, calcium chloride dosage and silicon dioxide dosage were also achieved. The rate of reaction based on diffusion-controlled process can be expressed by semi-empirical equations. The control steps of the gold and silver recovery process were investigated by the kinetic study, which provided theoretical guidance for the optimization of the method.

6

Natural Biosorbent for Oil Adsorption from Produced Water by Sedge Cane

Alatabe Mohammed Jaafar Ali, Faris Hamid Abdulmahdi, Husham Hala

Journal of Ecological Engineering

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2023

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Vol. 24, nr 10

67--76

EN

The sedge cane is a year-round natural plant that is regarded as one of the most significant grasses on the planet, and it usually causes major disposal concerns. As a result, employing sedge cane as a low-cost adsorbent to remove oil from produced water is helpful from both an economic and environmental standpoint. The response surface methodology is used to investigate the reaction optimization of oil removal using the sedge cane. The tests had three independent variables: adsorbent dosage, contact time, and temperature, as well as one response variable is (oil removal percent). According to the findings, the adsorbent dosage had the biggest impact on the percentage of oil removed. The findings predicted that employing sedge cane with 5 gm/L adsorbent dosage at 40 °C and 60 min contact time, the optimum condition for oil removal would be up to 95%. Fourier transforms infrared (FTIR) and scanning electron microscopy (SEM) were used to analyze the sedge cane. The results of the Langmuir, Freundlich, Toth, and Sips isotherm models were 0.9967, 0.4166, 0.956, and 0.9062, respectively. Compared to the other models, Langmuir model best characterized the adsorption process. The reaction’s kinetics were most accurately characterized by the PFO kinetic equation with 0.9382 for PFO, 0.8147 for PSO, and 0.7888 for the Elovich model. Temperature effects on thermodynamic parameters were investigated. The results of the testing showed that sedge cane is an effective adsorbent for eliminating oil from contaminated water.

7

Removal of Dyes by Adsorption Process Using Date Pits as Material Environmentally Friendly

Adachi Abderrazzak, El Ouadrhiri Faiçal, El Manssouri Ibtissam, Moussaoui Fatima, El Bourachdi Soukaina, Lahkimi Amal

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 8

181--193

EN

This study is based on the use of a natural material in the adsorption process to remove organic pollutants. The objective is to assess its effectiveness in adsorbing the organic pollutant MB from an aqueous solution, while operating in an open system. The DP bioadsorbent was characterized using FTIR and SEM. To determine their effect on adsorption efficiency, a number of variables were examined, including contact time, concentration of pollutant MB, adsorbent mass, pH, temperature, and adsorbent particle size. The effect of these variables on adsorption efficiency shows that a removal rate of 92.66% is achieved under optimum conditions, including a contact time of 35 minutes, a concentration of pollutant MB of 22.5 mg·l-1, an adsorbent mass (mDP) of 1.1 g·l-1 and a solution pH of 5.6. In addition, a progressive decrease in adsorption efficiency is observed with increasing temperature and adsorbent mass. On the other hand, this efficiency increases with increasing a concentration of pollutant MB. Three popular models, the Freundlich, Langmuir, and Dubin-Radushkevich models, have been used to examine the adsorption isotherms of the MB dye on DP. With a correlation factor of 0.98, it was discovered that MB adsorption monitored by the Freundlich isotherm. The Langmuir and Dubinin-Radushkevich models, however, do not adequately describe the data. The kinetic results were studied using the pseudo-first-order and pseudo-second-order equations, and show that MB dye adsorption on DP (adsorbent) follows the pseudo-second-order model. Also estimated were thermodynamic parameters such as (ΔH°), (ΔS°), (ΔG°), enthalpy, entropy, Gibbs free energy respectively to anticipate the character of adsorption. The results indicate that the adsorption process of MB on the bioadsorbent is exothermic. The results derived from the ΔG° values lead to the conclusion that the adsorption of MB occurs spontaneously.

8

Gas Nitriding of the Near-Beta-Titanium Alloy

Luk’yanenko Alexander G., Pohrelyuk Iryna M., Fedirko Viktor M., Molyar A. G., Trush Vasyl, Kravchyshyn T. M.

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 2

431--438

EN

The present research investigates the nitriding kinetics of the near-beta-titanium alloy of Ti-Al-Nb-Fe-Zr-Mo-V system at 750, 800, and 850°C in gaseous nitrogen at 105 Pa for 2, 4, and 8 h. The parabolic coefficient kp of the layer’s growth rate and the nitriding activation energy E are set as the kinetic parameters of the nitrided layer’s growth. The activation energy for the formation of a nitride layer is ~108 kJ/mol. The authors discuss the morphology of the nitride layers as well as their roughness and surface hardness. The study determines the effective diffusion coefficient for the growth of diffusion layers in the temperature range of 750...850°C: Def = D0 × exp (-E/RT), where D0 = 0.0177 m2/s; E = 215.7 kJ/mol. The friction coefficient of the disk from nearbeta-titanium alloy with a bronze block is lowered by significantly more than 10 times after gas nitriding, and the temperature in the friction zone is reduced by 2.5 times.

9

Study on the mechanism and kinetics of sulfuric acid leaching scandium from rich scandium anatase

He Fei, Gao Likun, Chen Long, Rao Bing, Shen Hairong, Peng Kebo, Gao Guangyan

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 3

art. no. 146171

EN

Scandium and its compounds have excellent properties, and are widely used in cutting-edge fields such as optics, electronics, and alloys. Thus, scandium is an important strategic metal. However, scandium is extremely sparsely distributed in the earth's crust, rarely occurs as an independent mineral, and requires a complex recovery process. Therefore, the study of the extraction of scandium is of great practical significance. This study examined the leaching test and kinetics of scandium under the acid leaching system of refractory anatase ore. Under appropriate two-stage countercurrent leaching conditions, the first stage of the particle size of fraction of -0.074 mm 82.6%, initial H2SO4 concentration of 6 mol/L, leaching temperature of 100 °C, acid/solid ratio of 3 ml/g, stirring speed of 300 rpm, and leaching time of 50 min; and the second stage of the initial H2SO4 concentration of 11 mol/L, leaching temperature of 150 °C, acid/solid ratio of 4 ml/g, stirring speed of 300 rpm, and leaching time of 50 min, a scandium leaching rate of 96.98% was achieved. The kinetics of scandium leaching conformed to a shrinking-core model, and sulfuric acid concentration and temperature were the most important parameters affecting the scandium leaching rate. The kinetic analysis of scandium leaching at different sulfuric acid concentrations showed that as the concentration increased, the sulfuric acid leaching of scandium changed from being chemical reaction-controlled to internal diffusion-controlled, and the apparent reaction order was 1.2429. The kinetics of scandium leaching at different temperatures showed that the sulfuric acid leaching of scandium was reaction-controlled and the apparent activation energy was 42.21 kJ-mol-1.

10

Kinetic modelling of flotation column and Jameson cell in coal

Karaca Sevgi, Ucar Ali, Sahbaz Oktay

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 5

art. no. 152848

EN

Physical enrichment technologies can be used worldwide in various coal washing plants to enrich up to 500 μm particle size. Conversely, coals smaller than this are discarded as waste, causing storage and environmental issues. In this regard, studies on coal below 500 μm in Turkey have recently acquired attraction. The Jameson flotation cell and flotation column, which have many uses worldwide but are not used throughout the plant in Turkey, were used to investigate the separation possibilities of coals below 500 μm. In the study, the flotation column and Jameson cell performances for three different particle sizes (-500+300, -300+212 and -212+106 μm) were compared. For the first time, both machines operated in a negative bias condition. In addition, the flotation kinetics of the machines were modelled with some critical operating parameters. Models illustrating the main and multiple effects of the parameters were developed using the data derived from the experimental results, and the models were statistically significant at the 95% confidence level. In the experiments performed with both flotation machines, the flotation rate increases with the decrease in particle size in general. According to the results, the velocity increase in the Jameson cell was 0.0050-0.0075 min-1 compared to the flotation column in the experiments performed in the size range of -500+300 μm, and the flotation rate constant increased approximately twice. In the size range of -212+106 μm, the difference became larger, and the flotation rate of the Jameson cell increased up to six times with a difference of 0.0450-0.0500 min-1.

11

Application of Pyrolox sorbent for vanadium(V) ions removal

Wójcik Grzegorz, Hubicki Zbigniew

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 2

art. no. 147974

EN

The sorption of vanadium(V) ions from acidic solutions using the Pyrolox sorbent was studied at varying ions concentrations, pH, contact time and temperature. The investigated ions were determined by means of graphite-furnace atomic absorption spectrometry (GF-AAS). The sorption capacity of vanadium(V) ions was examined in the pH range 2-10. The adsorption capacities of vanadium(V) ions depend on the pH values. Therefore, the initial pH 2 of vanadium(V) results in the highest adsorption capacities. The sorption vanadium(V) kinetics was investigated. The experimental data were analyzed using the pseudo-first-order, pseudo-second-order forms, Elovich, and intra-particle diffusion models. The kinetics of vanadium(V) sorption is described by the pseudo-first-order in the best way. The results indicate the endothermic process of V(V) ions sorption. The presented results of vanadium ions recovery from the solutions obtained as a result of spent catalysts leaching indicate the possibility of vanadium recovery.

12

Evaluation of CO2 adsorption capacity with a nano-CaO synthesized by chemical combustion/ball milling

Granados-Correa Francisco, Jiménez-Reyes Melania

Materials Science Poland

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2022

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Vol. 40, No. 2

257--269

EN

The adsorption of CO2 on a nano-calcium oxide (nano-CaO) adsorbent was investigated under different conditions of temperature and supply pressure, considering kinetic, isotherm, and thermodynamic parameters. CaO is a crystalline material with a high surface area and nanosized particles with high porosity, which showed rapid initial CO2 adsorption rates in the moderate temperature range studied. The adsorption was well described by the pseudo-second-order and the intraparticle diffusion kinetic models. The Langmuir isotherm model fitted the experimental data well, indicating a monolayer-type process. The thermodynamic parameters revealed that the CO2/nano-CaO adsorption was endothermic, not spontaneous, and proceeded via physical and chemical processes. The activation energy value confirmed that the mechanism involved is a chemical process. In addition, the nano-CaO adsorbent could be regenerated five times without any significant loss of performance or properties. All the obtained results reveal that this porous nanoadsorbent has huge potential to be applied for CO2-capture technologies on a large scale.

13

Kinetics of Pollutants Removal in Wetlands Influenced by Retention Time and Number of Plants Using Cyperus alternifolius

Rahman Danar Arifka, Priambodo Eka Wahyudi, Caturputranto Trisnadi Widyaleksono, Wahyudianto Febri Eko

Journal of Ecological Engineering

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2022

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Vol. 23, nr 12

37--43

EN

Constructed wetland is considered an alternative for domestic wastewater treatment in cities. This study serves to evaluate the removal capacity and kinetics of TSS, COD, phosphate, and surfactant in domestic wastewater with several plants of Cyperus alternifolius, through the use of the constructed wetlands treatment. The overall objective of the study was to determine the ability of Cyperus alternifolius to remove water pollutants in domestic wastewater in several plants. The domestic wastewater was contacted in a batch system. The results indicated that CWs had a good performance on COD, phosphate, and surfactant with removal efficiencies of more than 80%, with a retention time of 8 days and 5 plants. However, the removal of suspended solids was found limited, as shown that the TSS removal efficiency was under 40%. The first-order equation of kinetics described the degradation of pollutants. The q1/2 values, which were defined as the average removal loading prior to the half of the pollutant concentration being removed and represented the removal capacity without limitation of pollutants concentration, were moderately increased with an addition to the number of plants.

14

Ability of Response Surface Methodology to Optimize Photocatalytic Degradation of Amoxicillin from Aqueous Solutions Using Immobilized TiO2/Sand

Sulaiman Fadia A., Alwared Abeer I.

Journal of Ecological Engineering

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2022

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Vol. 23, nr 5

293--304

EN

The response surface method was applied to optimize operational factors in the solar photocatalytic process on the removal of Amoxicillin (AMOX) residues from aqueous solution using TiO2 immobilized on the sand as a catalyst. The results reveal that the degradation percentage of AMOX is 93.12%, when optimal conditions of pH=5, 75 mg/l of TiO2, 400 mg/l of H2O2, and 10 mg/l of AMOX concentration at 150 min irradiation time were used. Furthermore, the model’s expected response results have reasonable similarity with the actual data (R2 = 93.58%), demonstrating the efficiency of this method in making an accurate prediction. A second-order polynomial multiple regression model was used to evaluate the responses, which confirms that was a satisfactory adjustment with the achieved data through analysis of variance (R2 = 93.58%, R2adj = 91.48% and R2pred =89.68%). In addition, it is observed that the removal of undesirable compounds follows a pseudo-2nd order kinetic model with R2 = 0.9862. In conclusion, with the ease of usage of immobilized TiO2 and good photocatalytic efficiency, the findings showed the potential application to the antibiotics from an aqueous solution.

15

A Novel Rotating Fixed Bed Batch Reactor for Hexavalent Chromium Reduction

Sayed Doaa, Alturki Abdulaziz A., Farag Hassan, Khalifa Randa E., Abdel-Aziz Mohamed Helmy

Journal of Ecological Engineering

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2022

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Vol. 23, nr 11

273--280

EN

Hexavalent chromium reduction using iron powder has the advantages of being efficient and capable of degrading pollutants, as well as inexpensive and simple to procure. The performance of a new rotating fixed-bed batch reactor in treating aqueous solutions containing chromium hexavalent ions with iron powder was investigated. Two magnets were covered with iron powder and coupled with an isolated stainless-steel shaft in a new agitator design. Variables such as time, initial hexavalent chromium content, iron powder dose, rotational speed, and pH were investigated in order to discover the optimum chromium removal approach. The analysis of variance (ANOVA) was used to determine the experimental kinetics. Contact time of 21 minutes, initial Cr(VI) concentration of 30 ppm, iron powder dosage of 10 g, rpm of 276 and pH of 3 were determined to be the optimal conditions for removing hexavalent chromium.

16

Use of isoperibolic reaction calorimeter for the study of reaction kinetics of acetic anhydride hydrolysis reaction: Effect of acetic anhydride and water ratio

Kumar Rajendra, Tiwari Anurag Kumar

Chemical and Process Engineering

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2022

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Vol. 43, nr 2

255-–264

EN

Reaction kinetics of acetic anhydride hydrolysis reaction is being studied at a fixed reaction temperature and ambient pressure using an isoperibolic reaction calorimeter. Temperature versus time data along with heat and mass balance is used to determine the kinetics parameters i.e. activation energy and Arrhenius coefficient. It has been studied with the varying volumetric ratio of acetic anhydride and water; and kinetics parameters were compared and plotted for each ratio. Such a study has not been done previously to determine the kinetics dependency on varying the acetic anhydride water ratio. As the acetic anhydride hydrolysis reaction is exothermic in nature, the present study will help to decide the safe and suitable operating conditions such as concentration and temperature for conducting this reaction at plant scale. The kinetic data presented can be used further for the mathematical modeling and simulation of such exothermic hydrolysis reactions.

17

Optimization of fluoride removal using ultrasonically improved electrochemically generated adsorbent: A Taguchi approach

Junghare Kunjan C., Kodape Shyam M., Rathod Ajit P., Lataye Dilip H.

Chemical and Process Engineering

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2022

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Vol. 43, nr 2

109–-117

EN

Ultrasonically improved electrochemically generated adsorbent (UEGA) has been synthesized and used for adsorption of fluoride ions from fluoride laden waste water. UEGA was prepared in two major steps, firstly electrochemically generated adsorbent (EGA) was prepared using electrolytic method followed by ultrasonication treatment. Ultrasonication causes size reduction which leads to increase in surface area viz. active site which helps to enhance attachment of negatively charged fluoride ion on positively changed UEGA from waste water. UEGA was prepared at three different amplitude i.e. 50, 70 and 90% respectively. Taguchi optimization for defluoridation was carried out considering operating parameters such as initial concentration; contact time; adsorbent dose; and temperature. The results obtained demonstrated that adsorption showed different fluoride removal at varying frequency. This study proved that varying percentage amplitude of ultrasonication significantly affects defluoridation efficiency.

18

Thermodynamics and Kinetics Analysis on Carbothermic Reduction of Calcined Magnesite in Vacuum

Tang Qifeng, Ao Jinqing, Peng Biyou, Guo Biao, Yang Tao

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 3

1021--1026

EN

The carbothermic reduction of calcined magnesite in vacuum was studied. By thermodynamic analysis, the starting temperature of reduction reaction dropped from 2173 K to 1523 K when system pressure dropped from 1 atmosphere to 100 Pa. The experiments were carried out at different conditions under 10~100 Pa and the experimental results shown that the reduction extent of MgO improved by increasing the reaction temperature and time, the pellet forming pressure as well as adding fluoride as catalyst. The rate-determining step of carbothermic reduction process was gas diffusion with the apparent activation energy of 241.19~278.56 kJ/mol.

19

Production of lamellar cast iron EN-GJL-150 from local manganese-rich pig iron by modification of the melting process

Sitouah Noureddine, Cherfi Abdelhamid, Oualit Mehena, Zerizer Abdellatif

Advances in Materials Science

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2022

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Vol. 22, nr 4(74)

69--84

EN

In the present study, a modified duplex melting process was set up so as to be able to produce an EN-GJL-150 gray cast iron from a local manganese-rich pig iron. A descriptive statistics showed an average Mn and Si content in raw material such that: Mn % = 2.457±0.133 and Si % = 0.682±0.088. The demanganization process was run and monitored in a cascade of two industrial-scale furnaces: a rotary kiln and an electric arc furnace. The performed experiments indicated that: 1) the manganese content decreased from 2.45 % to 0.94 %, 2) the manganese oxidation obeys the first order kinetic model, 3) Brinell and Rockwell hardness’s decreased by 38.83% and 27.81% respectively, and 4) the produced cast iron has a pearlitic microstructure with a small fraction of ferrite (1 to 5%) in the matrix and traces of cementite. All results showed that the produced castings comply with the standards in force for EN-GJL-150 cast irons, similar to gray cast iron ASTM A48 Class 20.

20

An Innovative Project of a Bionic Robot for Social Applications in Felinotherapy

Litwin Sonia, Woźniak Klaudia, Olszewski Mariusz

Pomiary Automatyka Robotyka

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2021

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R. 25, nr 4

5--18

EN

The paper describes an innovative design of a bionic robot for applications in felinotherapy supporting hospital and home psychotherapeutic treatment of bedridden children and adults. The project was engineered by biomimicrating a biological cat, reaching its robotic model. Particular attention in this process was devoted to capturing the essence of feline motorics behavior and the possibility of mapping them in a mechatronic model. The geometry, kinematics and kinetics of this model were analyzed, creating assumptions for its practical implementation in the real mechanism of cat skeleton movement. The used software used the topology of elements in Autodesk Fusion 360 Simulation workspace by performing the critical elements of the mechatronic model in print using SLS technology. The work was also supported by a graphical simulation in the PyBullet environment.

PL

W pracy opisano innowacyjny projekt bionicznego robokota dla zastosowań w felinoterapii, wspomagającej szpitalne i domowe leczenie psychoterapeutyczne obłożnie chorych dzieci i dorosłych. Projekt zrealizowano inżyniersko przez biomimikrowanie biologicznego kota, dochodząc do jego robotycznego modelu. Szczególną uwagę w tym procesie poświęcono uchwyceniu istoty kocich zachowań ruchowych i możliwości ich odwzorowania w mechatronicznym modelu. Przeprowadzono analizę geometrii, kinematyki i kinetyki tego modelu, tworząc założenia jego praktycznej realizacji w rzeczywistym mechanizmie kociego ruchu. W wykorzystanym oprogramowaniu korzystano z topologii elementów w obszarze roboczym Autodesk Fusion 360 Simulation, wykonując krytyczne elementy mechatronicznego modelu drukiem, w technologii SLS. Prace wspomagano także symulacją graficzną w środowisku PyBullet.