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1

Elimination of Hexavalent Chromium Ions in Water Using a Manganese-Coated Pumice Adsorbent

Lestari Puji, Purwiandono Gani, Pramayshela Shike, Siswoyo Eko

Journal of Ecological Engineering

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2024

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Vol. 25, nr 1

229--235

EN

A natural pumice stone stone coated with manganese (Mn) has been prepared and utilized to remove hexavalent chromium (Cr(VI)) ions in water via adsorption process. Prior to the application, the natural pumice was ground, sieved, and immerse in a dilute HCl solution. The coating of Mn on the acid-activated pumice was carried out by soaking the powder in 0.5 M Mn(NO3)2 solution for 72 h. The characterisation of the produced pumice adsorbent was performed with scanning electron microscopy and fourier-transform infrared spectroscopy instruments. The adsorption of Cr(VI) onto Mn-coated pumices was optimum at pH 3. Both the Langmuir and Freundlich isotherm models could be used to describe the adsorption process. The rate of adsorption followed the model for pseudo- second-order kinetics. The maximum adsorption capacity of Mn-coated pumice towards Cr(VI) ions was 1.94 mg/g.

2

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.

3

Adsorption Equilibrium Studies on the Example of Nitrate Removal Onto Char Produced from Waste Tires

Skwarczynska-Wojsa Agata, Szatyłowicz Ewa, Skoczko Iwona

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 3

246--256

EN

There have been investigated potential evaluation of equilibrium adsorption isotherm for the removal of nitrates from water solutions using two types of char produced in commercial-scale pyrolysis based on recycled waste rubber tires. Liquid phase adsorption studies were performed under batch conditions and maximum adsorption capacity was determined. Equilibrium data were mathematically modelled using two-parameters Langmuir, Freundlich, three-parameters Redlich-Peterson, Toth, Dubinin-Radushkevich, Radke-Praushnitz, combined Langmuir-Freundlich and four-parameters Fritz-Schlunder, Marczewski-Jaroniec, Bi-Langmuir adsorption models. Obtained results revealed the potential use of the studied char adsorbents for nitrates removal from aqueous media (the maximum adsorption capacity at equilibrium 10.07 mg/g, have been achieved for CH-1 char). The Langmuir-Freundlich isotherm had the best fit for the adsorption experimental data over the whole concentration range. The highest percentage of NO3 removal efficiency onto CH-2 char achieved in NO3 initial concentration range from 26.44 to 66.55mg/L reaching values in the range of from 80.74 to 78.7%.

4

Thermal Recycling of Bentonite Waste as a Novel and a Low-Cost Adsorbent for Heavy Metals Removal

Shubber Mukhtar D. H., Kebria Daryoush Yousefi

Journal of Ecological Engineering

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2023

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Vol. 24, nr 5

288--305

EN

The objectives of this study are the thermal remediation of bentonite waste to convert non-hazardous material, and the use of the obtainedthermal recycling bentonite waste (TRBW) as a novel low-cost adsorbent for the removal of heavy metals from aqueous solution using the batch system. The origin of bentonite waste is a by-product from plants of spent engine oil recycling [PSEOR]. It was remediated in two stages, directly burning and in the electrical furnace at 700 °C for 100 minutes to eliminate oil residues and impurities. The tests of XRD, BET, FTIR, EDX, and SEM were accomplished to identify the chemical and physical characteristics of TRBW. After then, the examination of the ability of TRBW to adsorption of the fiveheavy metals (Zn, Ni, Cd, Cr, and Pb) with different experimental parameters such as initial concentration, adsorbent dose, temperature, pH, and contact time. Different models of isotherm, kinetic, and thermodynamic were utilized andthe results indicate that the nature of heavy metals adsorption onto TRBW was homogeneous. According to the maximum adsorption capacities, the metals ranked as Pb> Cd> Zn> Cr> Ni, and adsorption capacities were 94.97, 73.85, 39.56, 38.34, and 36.33 mg/g, respectively.

5

Removal of Ni(II) Ions by Citric Acid-Functionalised Aloe vera Leaf Powder – Characterisation, Kinetics, and Isotherm Studies

Al-Amrani Waheeba Ahmed, Abdullah Rohaizan, Megat Hanafiah Megat Ahmad Kamal, Suah Faiz Bukhari Mohd

Journal of Ecological Engineering

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2023

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Vol. 24, nr 4

217--227

EN

Aloe vera leaves (AVL), a by-product of agricultural waste, have been applied as a biosorbent for reducing Ni(II) ions in aqueous solutions. The biosorption capability of AVL powder was enhanced through chemical treatment with 0.10 M citric acid solution. Fourier-transform infrared (FTIR) spectrophotometer, scanning electron microscope coupled with energy dispersive X-ray (SEM-EDX), pH of point-zero-charge (pHPZC), and pHslurry analyses were used to study the surface, and chemical properties of citric acid-treated Aloe vera leaf powder (CAAVLP). The setting for experiments such as pH solution, CAAVLP dose, initial concentration, and biosorption time was investigated. Maximum Ni(II) ion biosorption capability was determined to be 48.65 mg/g based on the Langmuir model at pH 6, a CAAVLP dose of 0.02 g, initial Ni(II) concentrations of 5 to 50 mg/L and biosorption time of 120 min. The data for the isotherm and kinetics were well matched with the Freundlich and pseudo-second-order models, respectively, with high regression correlation (R2) and low chi-square (χ2) values. The presence of more-COOH groups after treating AVL with citric acid resulted in more Ni(II) ions being able to be removed.

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

Phosphoric Acid Treated Oil Palm Trunk Waste for Removal of Malachite Green – Kinetics and Isotherm Investigations

Zainon Abidin Zarifah Aisyah, Al-Amrani Waheeba Ahmed, Mohd Suah Faiz Bukhari, Ibrahim Shariff, Megat Hanafiah Megat Ahmad Kamal

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 6

33--43

EN

Dyeing operations in industries like textiles, paper, and leather are significant contributors to environmental pollution due to the release of harmful dyes. The current study aimed to examine the use of oil palm trunk (OPT) treated with phosphoric acid (PAOPT) to remove malachite green (MG) dye from aqueous solutions through batch adsorption experiments. Spectroscopic and quantitative tests were used to characterise the PAOPT adsorbent. The effects of initial solution pH (3–6), PAOPT dosage (0.02–0.10 g), and adsorption duration (0–120 min) were studied. The adsorption rate of MG followed a pseudo-second-order kinetic model with a high regression correlation (R2 ) and a low chi-squared value (χ2 ). The single-layer adsorption of PAOPT for MG was determined to be 217.23 mg/g at a pH of 6, 0.02 g PAOPT mass, 20 min contact time, and 298 K. The percentage of MG desorption from the loaded PAOPT using distilled water and 0.01 M HCl was 0% and 19.65%, respectively, indicating the possible involvement of electrostatic interactions between the dye and PAOPT, π-π interaction and hydrogen bonding. The experimental results of the current study and the assessment with other stated adsorbents indicate that PAOPT could be used as a cost-effective alternative adsorbent for MG removal.

9

The behaviour of tannic acid adsorption on fluorite surface: isotherm, kinetic and thermodynamic studies

Tangarfa Mariam, Semlali Aouragh Hassan Naoul

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 1

77--87

EN

Fluorite is an important mineral to produce hydrofluoric acid. As fluorite resources contain calcite as a gangue mineral, the separation between these two calcium containing minerals is difficult. Tannic acid is the most commonly used reagent as a depressant to separate fluorite from calcite by flotation. To enhance this separation, it is so primordial to understand tannic acid physicochemical reactivity via these minerals. Therefore, the aim of this work is to investigate the mechanism of tannic acid adsorption on the fluorite surface by experimental study using isotherm, kinetic and thermodynamic. Adsorption isotherm modelling results showed that the adsorption process is well described by Sips model. On the other hand, the kinetic and thermodynamic require firstly the adsorption study as a function of three main reactional parameters including initial tannic acid concentration, solution pH and temperature. This study showed that acidic pH as well as initial tannic acid concentration increase and temperature decrease promote the studied adsorption. These finding were then exploited to determine the adsorption mechanism by pseudo n order kinetic model adjustment to experimental kinetic data using nonlinear regression method. Obtained high correlation coefficient and low mean absolute error at 95 % confidence level showed good agreement of experimental kinetic data with the tested model. These results revealed that the mechanism of tannic acid adsorption onto fluorite was attributed to a chemical reaction. In addition, the thermodynamic study showed that the studied adsorption process was exothermic.

10

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.

11

Comparative Adsorption of Methylene Blue Dye on Hexane-Washed and Xanthated Spent Grated Coconut (Cocos nucifera L.): Isotherms, Thermodynamics, and Mechanisms

Khalid Khadijah, Hanafiah Megat Ahmad Kamal Megat, Al-Amrani Waheeba A., Malek Nik Ahmad Nizam Nik, Fatinathan Sharon

Journal of Ecological Engineering

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2022

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Vol. 23, nr 3

1--11

EN

A batch system investigated the application of two types of chemically modified biosorbents derived from spent grated coconut (Cocos nucifera) powder to adsorb methylene blue (MB) from aqueous solutions. The biosorbents were characterised by spectroscopic and quantitative analyses. The assessment of MB adsorption onto the investigated biosorbents was studied at different experimental conditions with different pHs (2–9) and different initial concentrations of MB (10–400 mg/L) at three different temperatures (298, 308, and 318 K). The maximum adsorption capacity (qmax) of xanthated spent grated coconut (XSGC) was higher than that of hexane-washed spent grated coconut (HSGC). The thermodynamic study indicated that the MB adsorption process was spontaneous for both biosorbents. Desorption of MB-loaded biosorbents was carried out using HCl, NaOH, and Na2EDTA solutions. A desorption ratio of more than 90% was obtained over three adsorption/desorption cycles for HSGC. However, XSGC demonstrated poor MB desorption, implying a stronger MB interaction with XSGC, which could be attributed to H-bonding, Yoshida H-bonding, n-π, and π-π bonding. The study showed that HSGC and XSGC could be applied as biosorbents to remove low MB concentrations from aqueous solutions.

12

Biochar as a Cadmium Scavenger in the Aquatic Environment Remediation: Date Seeds as Raw Material

Al-Tarawneh Amjad

Journal of Ecological Engineering

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2022

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Vol. 23, nr 3

270--280

EN

It was found that date seeds are suitable for biochar production due to their low moisture content 8.92%, low ash yield 1.05%, and high organic matter content 78.3%. The biochar was produced by pyrolysis at 350, 450 and 550°C. The effect of pyrolysis temperature on the physicochemical characteristics of biochar was investigated. It was found that the porosity, water holding capacity, ash content, pH, organic matter, fixed carbon, and the elemental content of Na, K, Ca, Mg, Fe, Mn, P, Zn, Ba, Cr, Cu, Ni, Pb, Ti, and V were increased along with pyrolysis temperature. Meanwhile, the biochar yield, bulk density, and the total content of N and S were decreased. The biochar was tested as a sustainable adsorbent to investigate the adsorption of Cd from contaminated water. The adsorption isotherms of Cd on biochar were determined based on Langmuir equation. The maximum adsorption of Cd at 25°C and pH 7 were 667, 714, and 833 mg/kg for the biochars produced at 350, 450, and 550°C, respectively. On the basis of the physicochemical characteristics of the biochar and the findings from Langmuir equation that showed the biochar produced at 550°C has the highest adsorption capacity for Cd, the desorption/adsorption experiment was carried out using the biochar produced at 550°C. The adsorption of Cd by biochar was directly proportional to the Cd concentrations. It was increased from 0.009 mmol/0.5g at 0.01 mmol Cd to 0.12 mmol/0.5g at 0.2 mmol Cd concentration. The desorption of Cd from biochar was increased proportionally to cadmium concentrations from 0.01 to 0.05 mmol and became constant above 0.05 mmol, regardless of the increment of cadmium concentrations. High retention potential for the cadmium that adsorbed within the biochar was proven in this study with desorption/adsorption percentage of 16%. These findings provide a successful example of date seeds converting into the sustainable adsorbent for Cd removal from aquatic environment to achieve the conception of eco-friendly production, which should be studied further.

13

Thiabendazole fungicide adsorption onto four agricultural soils collected from the Loukkos area of northwestern Morocco

El Azzouzi Laila, El Aggadi Sanaa, Ennouhi Mariem, Ennouari Abdelali, El Fadil Imane, Zrineh Abdallah

Ecological Chemistry and Engineering. S

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2022

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Vol. 29, nr 2

217--226

EN

A serious environmental problem can arise from the presence of pesticides in soils and waters. Hence, in this study we have carried out the adsorption of the Thiabendazole fungicide onto four soils collected from several areas in Morocco as Larache, Laouamra, Ksar kebir and Tlata drissana. Physicochemical properties, elemental analysis, X-ray diffraction (XRD) were investigated to characterise the four selected soils. The experimental equilibrium data were analysed using Langmuir, Freundlich models. The equilibrium data were best described by a Langmuir model for all adsorbents. The maximum estimated adsorption capacity was 0.747 mg∙g–1, 0.751 mg∙g–1, 0.473 mg∙g–1 and 1.083 mg∙g–1, for Larache, Laouamra, Ksar kebir and Tlata drissana soils, respectively.

14

Investigation of nickel adsorption onto low Jordanian zeolite dose: efficiency and Langmuir – Freundlich behaviour

Al-Ghazawi Ziad, Qasaimeh Ahmad, Al-Bataina Bilal

Journal of Water and Land Development

|

2021

|

no. 50

150--157

EN

In this work, nickel adsorption onto low Jordanian zeolite dose is being investigated. Natural zeolite doses were stirred continuously with nickel solutions in batch reactors at 180 RPM for 24 hours, where the temperature was set to 20°C. The pH was initially 4.5 and reached 5.2 at equilibrium. The removal efficiency of nickel reaches maximum value when the initial nickel concentration is around 1 ppm and then tends to decrease when the initial nickel concentration increases above 1 ppm. The optimal nickel removal reaches 65% when the initial nickel concentration is 1 ppm and the zeolite dose is 26 mg∙dm–3. This study investigates the behaviour of nickel removal and modelling isotherms below and above this critical peak point. At this level of zeolite dose, the adsorption does not follow either Freundlich or Langmuir isotherms, but rather, it follows Freundlich for the data plot just below the peak point with the highest coefficient of determination (R2) equals (0.98) when the zeolite dose is (26 mg∙dm–3), whereas it follows Langmuir for the data plot just above the peak point with the highest coefficient of determination (R2) equals (0.99) when the zeolite dose is (10 mg∙dm–3). These findings clarify the theory behind each isotherm and can be used to find new information for efficient treatment techniques.

15

Phenol Biosorption from Polluted Aqueous Solutions by Ulva lactuca Alga Using Batch Mode Unit

Abbas Mohammed Nsaif, Al-Hermizy Suadat Mustafa Mohammed, Abudi Zaidun Naji, Ibrahim Thekra Atta

Journal of Ecological Engineering

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2019

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Vol. 20, nr 6

225--235

EN

This paper is related to study the using sea lettuce (Ulva lactuca) as a low-cost adsorbent for removing the phenol compounds from aqueous solutions by adsorption under different operating conditions in a batch unit. The SEM and FTIR tests were performed to determine the morphological characteristics and the functional groups existing on the adsorbent material, respectively, while the surface area was identified by means of two techniques which were blue color method and BET method. The results of the adsorption experiments showed that the efficiency of the removal process is inversely proportional with initial concentration of phenol, pH and temperature; while the efficiency was directly proportional to adsorbent amount, agitation speed and treatment time. The results showed that the percentage of removal of phenol from processed water solutions ranged from 25.446% to 90.125%. The Langmuir and Freundlich isotherm models were chosen to estimate the amounts of phenol adsorption by the sea lettuce powder. The kinetic study shows that the adsorption was obeyed pseudo second order also the thermodynamic parameters were calculated.

16

Fluoride removal from groundwater by technological process optimization

Valentukeviciene Marina, Zurauskiene Ramune, Boussouga Youssef Amine

Ecological Chemistry and Engineering. S

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2019

|

Vol. 26, nr 1

133--147

EN

Fluoride removal from aqueous solutions was studied using nanofiltration and sorption techniques which have always been best key ways to deal with water contaminated by fluoride. In this presented work, we were firstly interested on fluoridated rejected water overcoming the drawback of RO membrane process of groundwater treatment plant in Baltic region (Kretinga, Lithuania). Opoka sorbent has shown effective results of fluoride sorption with efficiency higher than 77 %. In order to understand the sorption phenomenon and to validate the results obtained, we have applied experimental data on Freundlich and Langmuir isotherms which allow us to determine isotherms parameters (KF; 1/n and KL; qmax) and to confirm the experiment. Because of the unacceptable tariff of drinking water treated by RO, defluoridation with nanofiltration method is proposed in this study as a solution which can replace reverse osmosis technique. For that, tests of nanofiltration for fluoride removal were carried out at laboratory scale by using nanofiltration flat sheet membranes (NF270 and NF90).

17

Modele izoterm sorpcji stosowane w złożach gazu w pokładach węgla i w skałach mułowcowo-łupkowych

Smulski R., Imioło J., Nagy S.

Przemysł Chemiczny

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2018

|

T. 97, nr 6

899--902

PL

Omówiono modele adsorpcji metanu i węglowodorów w pokładach węglowych oraz w złożach łupkowych. Dobór odpowiednich modeli adsorpcji/desorpcji zależy głównie od struktury porowatej adsorbentu. Dla próbek skał łupkowych i węgla składających się głównie z mikroporów i mezoporów procesy sorpcji przebiegają zgodnie z typem pierwszym klasyfikacji IUPAC. Wykonano porównanie danych laboratoryjnych sorpcji z modelami izotermy Langmuira, Freundlicha, DR (Dubinina i Raduszkiewicza), DA (Dubinina i Astachowa) oraz BET (Brunauera, Emmetta i Tellera) celem najlepszego dopasowania. Wykonane badania potwierdziły zasadność stosowania modeli Langmuira i DR oraz częściowo BET do opisu zjawisk sorpcji w złożach niekonwencjonalnych gazu.

EN

Fundamentals and a review, with 12 refs. of models of adsorption of hydrocarbons in coal seams and in shale rock. The best fit was achieved by using the Langmuir and DR models and partly BET for the description of sorption phenomena in unconventional gas reservoirs.

18

Opis równowagi adsorpcyjnej z uwzględnieniem malejącej dostępności powierzchni w przebiegu mobilnej adsorpcji pojedynczego gazu na homogenicznym ciele stałym

Garbacz J. K., Kopkowska E., Rymian B.

Polish Hyperbaric Research

|

2018

|

nr 3(64)

25--38

PL

Wychodząc z ogólnego wyrażenia na kanoniczną sumę stanów mobilnej jednoskładnikowej monowarstwy adsorpcyjnej przedstawiono kolejne etapy procesu formułowania równania adsorpcji gazu na homogenicznej powierzchni stałego adsorbentu. Szczegółowo omówiono sposób wyprowadzenia całki konfiguracyjnej proponowanego modelu podkreślając rolę zarówno przyciągania jak i odpychania pomiędzy zaadsorbowanymi cząsteczkami. Zmodyfikowano wyrażenie na prawdopodobieństwo znalezienia molekuły w określonym punkcie powierzchni adsorbentu uzależniając tę wielkość od koncentracji adsorbatu. Wyrażenia na tzw. efektywną powierzchnię adsorbentu otrzymano adaptując dwuwymiarowe analogi równań stanu sztywnych kul, odpowiednio van der Waalsa (2D-vdW) oraz Reisa-Frischa-Lebowitza (2D-RFL). W rezultacie wyprowadzono dwa nowe równania adsorpcji różniące się szczegółami dotyczącymi odpychania adsorbat-adsorbat. Każde z tych równań poddano analizie teoretycznej w aspekcie dwuwymiarowych przejść fazowych. W obu przypadkach wykazano, że proponowane rozwiązanie dopuszcza możliwość wystąpienia dwóch przemian fazowych pierwszego rodzaju, to jest kondensacji gaz-ciecz oraz krzepnięcia, ciecz-ciało stałe. Weryfikację przedstawionej koncepcji uzupełniono opisem literaturowych danych doświadczalnych otrzymując bardzo dobrą zgodność teorii z eksperymentem.

EN

The subsequent stages of the process of formulation of the equation for gas adsorption on a homogenous surface of a solid adsorbent were presented based on the general expression for the canonical ensemble of the mobile single-component adsorption monolayer. The method of formulating the configuration integral of the proposed model was discussed in detail where the role both of the attraction and repulsion between adsorbed molecules was emphasised. The expression for the probability of finding a molecule in a specified point on a surface of an adsorbent was modified by determining its magnitude by the adsorbent concentration. The expression for the so-called effective surface of the adsorbent was obtained by adapting a two-dimensional analogue equation of state hard spheres – Van der Waals equation (2D-vdW) and Reis-Frisch-Lebowitz equation accordingly (2D-RFL). As a result, two new adsorption equations were formulated which differ in detail concerning the adsorbate-adsorbate repulsion. On each of these equations theoretical analysis was performed in terms of two-dimensional phase transformation. In both cases it was proved that the proposed solution allows for the presence of two-phase transformations of the first type which is the gas-liquid condensation and solidification liquid-solid. The verification of the given approach was supplemented by the description of the experimental data given in reference literature and by obtaining a very good correlation between the theory and experiment.

19

Chloroorganic Pesticide Adsorption from Water Solution Using Sewage Sludge Vermicompost as a Natural Sorbent

Ignatowicz K.

Journal of Ecological Engineering

|

2018

|

Vol. 19, nr 4

123--128

EN

Dozens of thousands of tons of pesticide waste have been stored since 1950s. The corrosion of concrete bunkers and wells where the expired pesticides are deposited causes the risk of toxic leakage due to deteriorating conditions of these constructions. Such hazardous spill might be transported by underground waters in the form of so-called underground inflow and subsequently might reach a network of surface waters. Evaluating the adsorption potential of natural sorbent for pesticide was the main goal of this research. The adsorption balance was examined in order to analyze the influence of the adsorption mechanism of HCH molecules on vermicompost. The adsorption of HCH isotherms by vermicompost at constant temperature was tested experimentally. The Freundlich, Langmuir and BET’s adsorption isotherm models describe the experimental data within the acceptable error ranges. The Freundlich model proved to be more suitable for the experimental data. The form of isotherms indicates that HCH is adsorbed as a monolayer; therefore no obstacles occur in order for water and pesticide molecules to cover the adsorption surface.

20

Adsorptive removal of aqueous phase crystal violet dye by low-cost activated carbon obtained from Date palm (L.) dead leaflets

Sulyman M., Namieśnik J., Gierak A.

Inżynieria i Ochrona Środowiska

|

2016

|

T. 19, nr 4

611--631

EN

Up to now, water pollution is still one of the important issues and challenges worldwide, due to its environmental, economic and human life impacts. It is also remains a challenge to environment scientists and technologists. Nowadays, the textile dyeing industry is considered one of the largest water consuming industries and produces large volumes of colored wastewater in its dyeing and finishing process. In this study, date palm tree leaflets (DPL) has been selected as a natural renewable source for the production of a new activated carbon (AC) utilized for the removal of crystal violet (CV) from water-dye system using a batch mode technique. The experiments studies were carried out at different initial dye concentration, contact time, adsorbent dose, and pH. The sorption exhibited high efficiency for CV adsorption and the equilibrium state could be achieved in 30 minutes for the different CV initial concentrations. CV removal was proved to increase with the increase in ACDL dose, pH, and contact time. Agitation rate and total volume of the reaction mixture were kept at 200 rpm and 20 mL respectively. The applicability of Langmuir and Freundlich isotherm equations was investigated and it was found that experimental data fitted very well to both Freundlich and Langmuir models. The maximum adsorption capacity (qm) was found to be 36.63 mg/g.

PL

Poziom zanieczyszczenia wody jest jednym z najważniejszych problemów do rozwiązania i wyzwań dla technologii remediacyjnych. Także przemysł farbiarski ma wpływ na zanieczyszczenie wód powierzchniowych ze względu na wytwarzanie dużych ilości ścieków powstałych w procesie barwienia i wykańczania materiałów. Liście palmy daktylowej zostały wybrane jako naturalne, odnawialne źródło materiału organicznego do wytwarzania węgla aktywnego, który może być wykorzystany w procesie usuwania fioletu krystalicznego. W trakcie badań zbadano wpływ stężenia barwnika, czasu kontaktu, masy złoża węgla aktywnego oraz pH wody na efektywność procesu usuwania barwnika. Na podstawie uzyskanych wyników można stwierdzić, że izotermy Freundlicha i Langmuira dobrze opisują przebieg procesu adsorpcji fioletu krystalicznego na złożu węgla aktywnego uzyskanego z martwych liści palmy daktylowej.