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1

Decolorization of Cationic Dye from Aqueous Solution by Multiwalled Carbon Nanotubes

Ahmed Salwa H., Rasheed Ekehwanh A., Rasheed Luma A., Abdulrahim Firas R.

Journal of Ecological Engineering

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2024

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Vol. 25, nr 2

72--84

EN

Methylene blue is a synthetic and cationic dye that finds utility in different fields including pharmaceutical, paper, textile, printing, carpet, and photography industries. Adsorption is a very effective technique to decolorize contaminated wastewater. This study aimed to determine the efficacy of Multiwalled Carbon Nanotubes (MWCNTs) as an adsorbent for decolorization of MB dye from aqueous solutions. The study examined various characteristics affecting adsorption, including concentration of dye, pH value, dosage of MWCNTs, and contact time. The results that growing the adsorbent dosage from (25 to 120) mg increased the dye efficiency rate from 62% to 98%, respectively, were shown. The study also evaluated pH, which is among the most critical factors influencing removal efficiency. The best pH for the removal efficiency was 6 at an initial concentration of MB dye 20 mgL-1, a contact time 60 min, and an MWCNT dosage 100 mg. Langmuir, Freundlich, and Temkin isotherms were used to describe the adsorption equilibrium. The Langmuir isotherm with an R2 value of 0.9968 and a maximum capacity for adsorption of 19.6 mgg-1 provided a suitable fit for the data of the experiment. In comparison between the suitability of kinetic models pseudo-first-order, pseudo-second order, and Weber–Morris, the kinetics model’s correlation value was shown to be greater than that of the pseudo-second order kinetic model with an R2 value of 0.9982.

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

Synthesis of nanoscale zero-valent iron doped carbonized zeolitic imidazolate framework-8 for methylene blue removal in water

Chen Shuai, Qiao Lemeng, Feng Xuejiao, Huang Yufu, Gao Guilan, Guan Jie, Lin Donghai

Polish Journal of Chemical Technology

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2023

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Vol. 25, nr 1

12--19

EN

Nanoscale zero-valent iron-doped carbonized zeolitic imidazolate framework-8 (nZVI/CZIF-8) was prepared by carbonation of ferric nitrate and ZIF-8 at 800 °C and used as an adsorbent to remove methylene blue (MB) from water. The synthesized nZVI/CZIF-8 has a specific surface area of 806.9 m2/g, a pore volume of 0.86 cm3/g and an nZVI content of 1.35%, respectively. Both the nZVI/CZIF-8 and CZIF-8 have identical functional groups of O-H, C-H and C=C. With the increase of CZIF-8 size, MB removal rate increased. The doping of nZVI increased the MB removal percentage from 74.5% for ZIF-8 to 96.2% within 80 min for nZVI/CZIF-8. The MB removal percentage increased with the dosage of nZVI/CZIF-8. The MB adsorption with the adsorbents conforms to the Freundlich adsorption isothermal model and the removal rate fitted well to a pseudo-first-order model. The results demonstrate the feasibility of synthesizing high active and stable nZVI/CZIF-8 particles.

4

Hydrothermal Synthesis and Characterization of Sodium Bismuth Titanatefor Photocatalytic Applications

Mesrar Mohammed, Elbasset Abdelhalim, El Mrabet Imane, Zaitan Hicham, Abdi Farid, Echatoui Nor-Said, Lamcharfi Taj-dine

Journal of Ecological Engineering

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2023

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Vol. 24, nr 10

185--197

EN

Sodium bismuth titanate (Na0.5Bi0.5TiO3, abbreviated NBT) ceramics underwent concurrent successful synthesis on the basis of the hydrothermal method. A selected low-temperature process of thermal treatment was conducted to obtain a highly dense morphology, produced from high purity carbonates and oxides serving as initial precursors. The presence of well-crystallized NBT in the rhombohedral phase was also found at hydrothermal temperatures of 200 °C. X-ray diffraction (DRX), Raman spectroscopy, Infrared spectroscopy (IR), and Scanning electron microscopy (SEM) analysis enabled to verify the structure, phase, morphology, and composition of the used samples. NBT ceramics exhibit features specific to relaxor ferroelectrics, with a diffusion exponent γ of up to 1.5 to promote their applications in micro-electromechanical and energy harvesting systems. The photocatalytic behaviors of NBT powders have been assessed by means of the degradation of methylene blue (MB) through UV-light irradiation. The samples prepared with precursors having a Na/Bi ratio of 0.5/0.5 showed the highest methylene blue (MB) photodegradation rate of 100% under UV irradiation for 420 minutes. In addition, photocatalytic activities under different masses and pH values were discussed for the first time. In addition, the photocatalyst has excellent stability, due to the larger particle size and surface area, which opens up new possibilities for the design of multi-component photocatalysts for future applications. The photocatalytic mechanism for the degradation of organic dyes (MB) has been principally assigned to the photoreduction process caused by superoxide radical anions (•O2−) and hydroxyl radicals (•OH).

5

Comparison of Two Biosorbent Beads for Methylene Blue Discoloration in Water

Purwiandono Gani, Lestari Puji

Journal of Ecological Engineering

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2023

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Vol. 24, nr 8

137--145

EN

In this study, alginate-encapsulated biosorbents have been prepared from agricultural wastes viz. peanut shells and rice husks. Biosorbents in this study were referred as En-PS and En-RH for the adsorbents prepared from peanut shells and rice husks, respectively. The characteristics of the adsorbents were thoroughly investigated using scanning electron microscope, X-ray diffractometer, surface area analyzer, and Fourier-transform infrared spectrophotometer instruments. The prepared biosorbents were used as adsorbents for cationic methylene blue (MB) dye in water. The encapsulation process using sodium alginate simplified the separation of adsorbent from the water after the adsorption process. The adsorptions of MB onto both adsorbents followed the pseudo-second order model and fitted both Langmuir and Freundlich isotherm models. Thermodynamic studies revealed that the adsorption of MB onto En-PS and En-RH was a spontaneous and endothermic process with the ΔG° reaction of -1.694 and -2.028 kJ/mol at the room temperature, respectively. Biosorbents could be used in the adsorption-desorption process for up to 3 cycles.

6

Ammonium-Assisted Intercalation of Java Bentonite as Effective of Cationic Dye Removal

Hakim Yusuf Mathiinul, Mohadi Risfidian, Mardiyanto, Royani Idha

Journal of Ecological Engineering

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2023

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Vol. 24, nr 2

184--195

EN

Modification of Java bentonite assists by the multi-step intercalation of sodium and ammonium ions under low-temperature preparation. The adsorbent was examined to remove rhodamine B and methylene blue dyes in an aqueous solvent. The analysis of structural changes conducted by XRD analysis showed the peak shifting from 19.89° to 16.1° and specific peak spectra FTIR of 2846.93 cm-1 due to increase basal spacing from ammonium intercalation. The total capacities of NH-bentonite, Na-bentonite, and Natural Bentonite adsorption to rhodamine B were 192.308 mg/g, 136.936 mg/g, and 116.279 mg/g, respectively, under acidic conditions. Furthermore, the total capacities of NH-bentonite, Na-bentonite, and Natural Bentonite adsorption to methylene blue were 270.27 mg/g, 158.73 mg/g, and 136.986 mg/g, respectively, under alkaline conditions. The adsorption mechanism described that the rhodamine B and methylene blue removal occurred endothermically, was feasible, and adhered to the kinetics model of pseudo-second-order and Langmuir isotherm. It concluded that the modified Java Bentonite from multi-step intercalation is affordable and effective as wastewater treatment.

7

Polyoxometalate Intercalated Layered Double Hydroxide for Degradation of Procion Red

Hanifah Yulizah, Mohadi Risfidian, Mardiyanto, Lesbani Aldes

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 6

109--116

EN

The synthesis and characterization of layered double hydroxide (LDH) and intercalated polyoxometalate were presented.. The growth of polyoxometalate on Ni/Mg layered double hydroxide for degradation procion red (PR) was reported. The degradation parameters and organic dye removal efficiency of Zn/Mg-LDH and both composite LDH-polyoxometalate were determined by considering factors such as pH of dye solution, catalyst dosage, and time as variables of degradation. X-Ray, FTIR, and SEM spectroscopy confirmed the layered double hydroxide structure. XRD and FTIR analysis confirmed the single-phase of the as-made and polyoxometalate intercalated LDH. SEM images show the formation of aggregates of small various sizes. The catalytic activity of the material was evaluated in the degradation of PR as a model pollutant. The result showed that MgAl-SiW12O40 has a good degradation capacity for PR as compared to MgAl-PW12O40, ZnAl-SiW12O40, and ZnAl-PW12O40. The result shows that the LDH composite presents stability and has good photocatalytic activities toward the reduction of methylene blue. The materials utilized for the fifth regeneration are indicated by the FTIR results, which verified the LDH composite structure. The photodegradation process of procion red for immaculate ZnAl-LDH, MgAl-LDH, ZnAl-[PW12O40], ZnAl-[SiW12O40], MgAl-[PW12O40], MgAl-[SiW12O40] amounted to 68%, 70%, 56%, 79%, 74%, and 80%, respectively. The capacity of LDH-polyoxometalate composite material to successfully photodegrade, as measured by the percentage of degradation, revealed an increase in photodegradation catalysis and the ability of LDH to regenerate.

8

Removal of methylene blue from aqueous solutions via adsorption on activated biocarbon obtained from post-extraction residue

Przytulska Agata, Gargol Mateusz, Gil-Kowalczyk Małgorzata, Nowicki Piotr

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 2

art. no. 146709

EN

This paper deals with adsorption of a cationic dye – methylene blue - on the activated biocarbon obtained via chemical activation of horsetail herb post-extraction residue. The effects of initial dye concentration, temperature, solution pH, as well as the phase contact time on the adsorption effectiveness have been tested. The adsorbent prepared was characterized based on the results of elementary analysis, surface area measurements, thermal analysis as well as determination of the acid-base nature of its surface. It has been shown that micro/mesoporous horsetail herb-based activated biocarbon exhibits a significantly higher ability to methylene blue uptake than the commercial activated carbon prepared from peat. It has been also found that the adsorption capacity increases with the increasing initial dye concentration in the solution and the phase contact time. The maximum adsorption toward methylene blue was found at pH=12 and at temperature of 40 C. A better fit to the experimental data was obtained with a Langmuir isotherm than Freundlich one, whereas better fit of the kinetic data was achieved using the pseudo-second order model.

9

Improving the Performance of Mg/Cr LDH by Forming Metal Oxides Mg/Cr-Ni Using Coprecipitation Method as Adsorbent for Cationic Dyes

Yuliasari Nova, Badri Arini Fousty, Siregar Patimah Mega Syah Bahar Nur, Palapa Neza Rahayu, Mardiyanto, Mohadi Risfidian, Lesbani Aldes

Journal of Ecological Engineering

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2022

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Vol. 23, nr 6

67--74

EN

This study aimed to determine the adsorption capacity of rhodamine-B (Rh-B) and methylene blue (MB) on Mg/Cr-Ni adsorbents. The Mg/Cr-Ni adsorbent was synthesized by the coprecipitation method. The results of the characterization of Mg/Cr-Ni using XRD analysis showed the formation of oxides at an angle of 2θ = 31.726°, 33°, and 45.44°. The surface area of Mg/Cr-Ni is 23.139 m2/g. The adsorption capacity test for Mg/Cr-Ni for Rh-B and MB were 85.470 mg/g and 166.667 mg/g, respectively. The adsorption kinetics model followed the pseudo second order (PSO). The adsorption process is endothermic and occurs spontaneously at any temperature. Mg/CrNi showed stability in the adsorption process of Rh-B and MB for 5 regeneration cycles.

10

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.

11

Aegle marmelos leaf extract based synthesis of nanoiron and nanoiron+Au particles for degradation of methylene blue

Tarangini Korumilli, Jagajjanani Rao K., Wacławek Stanisław, Černík Miroslav, Padil Vinod V. T.

Ecological Chemistry and Engineering. S

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2022

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Vol. 29, nr 1

7--14

EN

In this study, nanoiron and nanoiron+Au particles were synthesised using aqueous Aegle marmelos extract using a facile and one-pot approach. Lower size non-magnetic nanoiron (~34 nm) and nanoiron (~34 nm)+Au particles (1 to 1.5 μm) were produced from the same medium individually. Nanoparticles suspension behaviour and structural characterisations were carried out by UV-Vis spectroscopy, electron microscopy and by X-ray diffraction techniques. Primarily, for synthesis, a simple bioreduction approach generated amorphous nanoiron particles, which on annealing produced magnetic maghemite, γ-Fe2O3 type nanoparticles with sizes 100 to 1000 nm. Posteriorly, the bioreduction process also produces nanoiron+Au particles and can be used for multifunctional applications. As a model application, catalytic application of the as-prepared nanoiron and nanoiron+Au particles towards methylene blue, a thiazine dye degradation is investigated and found to be effective within 20 min. Langmuir-Hinshelwood kinetic model was exploited to know the degradation behaviour, and the model was found to be fit based on R2 values with the observed experimental data. We suggest that the formed highly stable nanoiron particles with in situ stabilisation offer benefits like consistency, environmental friendliness and suits well for large-scale applicability.

12

Enhancement photocatalytic activity of Mn doped CdS/ZnO nanocomposites for the degradation of methylene blue under solar light irradiation

Sivaranjani Kaliyappan, Sivakumar Santhanam, Dharmaraja Jaganathan

Advances in Materials Science

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2022

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Vol. 22, nr 2(72)

28--48

EN

In this study, Mn doped CdS/ZnO nanocomposites synthesized by co-precipitation method and its photocatalytic activity was tested using methylene blue under solar light irradiation. The prepared hybrid nanocomposites are characterized by using different physicochemical techniques including XRD, FESEM, EDX, TEM, UV-vis DRS and PL analysis. From the XRD analysis, Mn doped ZnO/CdS nanocomposite diffraction peaks only reflect the binary crystalline structures of ZnO and CdS. However, there is no characteristic peak of Mn is found that may be because of low content of Mn doped on ZnO/CdS. But Mn (2.9 wt%) was detected in the Mn doped ZnO/CdS nanocomposite, which was measured by EDX analysis. The FESEM and TEM results exhibit the surface particle of Mn doped ZnO/CdS nanocomposite which have spherical nature and confirmed the formation of Mn doped ZnO/CdS nanocomposites. The photocatalytic degradation results have revealed that the Mn doped CdS/ZnO nanocomposites exhibit admirable activity toward the photocatalytic degradation of the MB. The reason for excellent photocatalytic activity of Mn doped CdS/ZnO nanocomposites indicates the absorbance band shifted to red region and reduction of recombination of photogenerated electron-hole, which is in good agreement with UV-visible DRS analysis and PL study results. The fitted kinetic plots showed a pseudo-first-order reaction model and the appropriate rate constants were found to be 0.0068 min−1, 0.00846 min−1, and 0.0188 min−1, for ZnO, 25 % CdS/ZnO, and 0.8 mol% Mn doped CdS/ZnO nanocomposites, respectively. The maximum photocatalytic activity was achieved by 0.8 mol% Mn doped CdS/ZnO nanocomposites with a 95% degradation efficiency of MB. Hydroxyl and superoxide radicals, having a vital role in the degradation of MB, confirmed scavenging experiments. In addition, the recycling tests displays that the Mn doped CdS/ZnO nanocomposites have shown good stability and long durability. The enhanced photodegradation activity of Mn doped CdS/ZnO nanocomposites indicates the potential of the nanocomposite for the treatment of organic pollutants from the textile wastewater.

13

Effect of Water Parameters on Decolourization Efficiency of Organic Dyes by Dielectric Barrier Discharge Plasma

El Shaer Mohamed, Habib Mohamed, Mobasher Mona

Ecological Engineering & Environmental Technology

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2021

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Vol. 22, iss. 1

74--82

EN

Nonthermal plasma discharge is used for the decolourization of dyes used in textile industry. Two dyes were considered, namely methylene blue and malachite green in aqueous solution. Plasma was generated by a Pin-water surface DBD between a metal pin electrode placed in air and the surface of an aqueous dye solution filling a glass container. Active radicals, especially hydroxyl radicals, generated by plasma in air penetrated the aqueous dye solution and induced the oxidizing reactions leading to the dyeing material disintegration. The measurements of solution parameters, including pH, oxidation-reduction potential, and conductivity can help to optimize the plasma decolourization efficiency of the two dye solutions. It was found that the pH values of the two dye solutions decrease with the increasing plasma treatment time. This is accompanied by an increase of the oxidation-reduction potentials and conductivities. The concentration of hydrogen peroxide formed in the two dye solutions during plasma treatment was found to increase with the plasma treatment time. The decolourization efficiencies of the two dye solutions increase with plasma treatment time and can be related to the solution parameters, including reduction of the pH values, increase in the oxidation-reduction potentials as well as solution conductivities and increase of hydrogen peroxide during the plasma treatment time.

14

Gold nanoparticles in an enhancement of antimicrobial activity

Wanarska Ewelina, Maliszewska Irena

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 6

269--279

EN

The effect of antimicrobial photodynamic therapy (aPDT) on Gram-positive bacterium Staphylocccus aureus was studied. Methylene blue (MB) at non-toxic concentration of 31.25µg/ml was used as a photosensitizer. LEDs diodes were used as a light source to study the effect of methylene blue alone and the MB-gold nanoparticle mixture on the viability of S. aureus cells. Biogenic gold nanoparticles (biolAuNPs, 10ppm) and chemically synthesized gold nanoparticles (chemAuNPs, 3ppm) were tested as enhancement agents. In the presence of MB alone as a photosensitizer, the killing effect was about 92% after 30min of irradiation. The aPDT therapy was enhanced by addition of biolAuNPs and chemAuNPs and killing rate of S. aureus was 95-96% after 30min of irradiation. The probable mechanism of enhancement of MB-mediated photodynamic bactericidal efficacy against S. aureus in the presence of gold nanoparticles is discussed leading to the conclusion that colloidal gold increases the accumulation of MB in bacterial cells.

15

Development of Adsorbent from Phytoremediation Plant Waste for Methylene Blue Removal

Alshekhli Atyaf Farooq, Hasan Hassimi Abu, Muhamad Mohd Hafizuddin, Abdullah Siti Rozaimah Sheikh

Journal of Ecological Engineering

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2020

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Vol. 21, nr 8

207--215

EN

Dyes are considered to be hazardous, have low biodegradability and can affect the human health as well as the aquatic life cycle. This research investigated the methylene blue (MB) removal using an activated carbon matrix of Scirpus grouss (waste that was initially used for phytoremediation of soil). The experiment was conducted in a flask containing 0.5 g AC-SC with MB concentrations of 5 and 15 mg/L. The adsorption was monitored for 120 sec. The results showed complete removal of MB within a contact time of 30 sec using 6-AC. The surface morphology analysis showed that at 6-AC, the structure was more porous. The ultimate potential of activated carbon prepared from the phytoremediation plant waste would be the best alternative for the water and wastewater treatment, while it provides an alternative to the phytoremediation waste management process.

16

Study of methylene blue adsorption by modified kaolinite by dimethyl sulfoxide

Lellou Salima, Kadi Samir, Guemou Laid, Schott Jacques, Benhebal Hadj

Ecological Chemistry and Engineering. S

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2020

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Vol. 27, nr 2

225--239

EN

Tamazert kaolin was modified with dimethyl sulfoxide (DMSO). The starting material and resulting from the intercalation were characterized by X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy (SEM). Intercalation caused considerable changes in our clay by increasing the basal spacing to 11.22 Å, an intercalation rate of 98 %. The adsorption of methylene blue was studied as a function of pH, contact time, temperature, dye concentrations and adsorbents. Kinetic data have been adequately described by the pseudo-second order and intraparticle scattering model. The adsorption isotherm is in good agreement with the Redlich-Peterson model. A change in thermodynamic values (ΔH°, ΔS° and ΔG°) was observed after intercalation. Adsorption became non-spontaneous exothermic and ordered.

17

Recycling of oil fly ash in the adsorption of dyes from industrial wastewater

Primerano Patrizia, Milazzo Maria Francesca

Ecological Chemistry and Engineering. S

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2020

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Vol. 27, nr 2

257--270

EN

The use of oil fly ash after the recovery of heavy valuable metals was investigated. More specifically, its use, as an adsorbent of dyes from industrial wastewater, was evaluated. Methylene blue was used as a model compound to study the adsorption capacity of the proposed carbonaceous residue from metal recovery treatments. The effects of contact time, initial dye concentration, and absorbent dose were investigated. The maximum amount of dye was adsorbed after one hour. Moreover, 1-3 g of residues were necessary for the removal of 200-1000 mg dm–3 from 0.050 dm3 of contacted solution. The Langmuir isotherm model was in good agreement with the adsorption equilibrium data, indicating a maximum monolayer saturation capacity of approximately 40 mg/g at 25 °C. High abatement efficiencies (up to 99 %) were obtained, and the adsorbed dye was released almost immediately by re-contacting with water. The adsorption capacity was at least four times lower than that of commercially available active carbon. The double treatment of oil fly ash with deionised water and hydrochloric acid allows for the extraction of over 85 % of the vanadium, iron, and nickel content in the ash. However, the negligible or zero cost of solid residues, otherwise disposed in landfills, indicates their potential as a valid alternative. The use of oil fly ash for both recovery of heavy valuable metals and the subsequent removal of dyes from wastewater suggest a zero-waste process.

18

Transport of Organic Dyes in Systems Containing Humic Acids

Rybarik Jan, Sedlacek Petr, Klucakova Martina

Inżynieria Mineralna

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2019

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R. 21, nr 1

159--162

EN

This work is focused on transport organic dyes in systems containing humic acids as active reaction agent. Methylene blue was used as a model organic dye which can behave as pollutant and influence many processes in nature. Transport of pollutants in nature is strongly affected by interactions with humic acids or natural organic matter. Their influence is dependent on affinity of pollutant to content and strength of active binding sites. Two different humic samples are used in this study in order to compare their properties on transport of organic dye. Both humic acids are used in original extracted form as well as in the form of samples with selective blocked functional groups.

PL

Niniejsza praca koncentruje się na transporcie barwników organicznych w systemach zawierających kwasy huminowe jako środek aktywny. Błękit metylenowy wykorzystano jako modelowy barwnik organiczny, który może zachowywać się jak substancja zanieczyszczająca i wpływać na wiele procesów w przyrodzie. Na transport zanieczyszczeń w przyrodzie silnie wpływają interakcje z kwasami huminowymi lub naturalną materią organiczną. Ich wpływ zależy od powinowactwa substancji zanieczyszczającej do zawartości i siły aktywnych miejsc wiązania. W badaniu tym zastosowano dwie różne próbki humusowe w celu porównania ich właściwości w transporcie barwnika organicznego. Oba kwasy humusowe stosuje się w oryginalnej postaci ekstrahowanej, jak również w postaci próbek z selektywnie zablokowanymi grupami funkcyjnymi.

19

Photocatalytic degradation of reactive dyes and real textile composite wastewater using TiO2/MWCNT nanocomposite under UVA and UVA-LED irradiation. A comparative study

Kumar Deivanai Suresh, Sellappa Kanmani

Environment Protection Engineering

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2019

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Vol. 45, nr 2

95--116

EN

Nano TiO2 and TiO2/MWCNT nanocomposite synthesized by the sol-gel method were characterized by XRD, BET, SEM, EDAX and FTIR techniques. These nanoparticles were used for photocatalytic decolorisation and degradation of three different reactive dyes such as Reactive Orange 16 (RO 16), Reactive Yellow 145 (RY 145) and Reactive Red 195 (RR 195) and real textile composite wastewater under the UVA and UVA-LED irradiation at room temperature. The maximum color removal of 96% and COD removal of 72% were achieved after 5 h in the presence of TiO2/MWCNT and H2O2 under UVA-LED irradiation. The kinetic studies obey pseudo-first order kinetics which is discussed in terms of the Langmuir–Hinshelwood kinetic model. The maximum degradation of 50% was achieved after 5 h in the presence of H2O2 using TiO2/MWCNT/UVA-LED for real textile composite wastewater. This study revealed that TiO2/MWCNT has improved the photocatalytic activity when compared to that of bare TiO2 under similar conditions. UVA-LED could be an alternative light source for the replacement of the conventional UV light for the photocatalytic treatment of reactive dyes.

20

Equilibrium, kinetics and thermodynamic study of the adsorptive removal of methylene blue from industrial wastewater by white cedar sawdust

Gardazi Syed Mubashar H., Shah Jehanzeb Ali, Ashfaq Tayyab, Sherazi Tauqir A., Ali Muhammad Arif, Pervez Arshid, Rashid Naim, Iqbal Javed, Amin Bilal Ahmad Zafar, Bilal Muhammad

Environment Protection Engineering

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2019

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Vol. 45, nr 3

5--22

EN

The study evaluated the adsorption potential of white cedar sawdust (WCS) for dye removal. WCS was chosen from five preferred, abundant waste biomasses from Pakistan. Various parameters such as contact time, adsorbent dose, dye concentration, pH, and particle size were optimized for methylene blue (MB) dye adsorption. The adsorbent was characterized by FTIR, SEM, EDX and BET analyses. The surface area of the adsorbent was 1.43 m2·g-1 and pore volume was 0.000687 cm3·g-1. The adsorption data best fitted the isotherm models of Langmuir, Temkin, Dubinin–Radushkevich, and Freundlich. The maximum experimental adsorption capacity obtained was 55.15 mg·g-1, which was in close agreement to the calculated adsorption capacity. Fitness of the pseudo-second order kinetics suggested chemisorption as the rate-limiting step. Thermodynamic study for adsorption was carried out to evaluate the Gibbs free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°). The negative values ΔG° at the examined temperature range confirmed the spontaneous adsorption of MB onto WCS.