Two-fold 2D + 2D → 2D interweaved rhombus (4,4) grid: synthesis, structure, and dye removal properties in darkness and in daylight

2019 ◽  
Vol 48 (3) ◽  
pp. 1095-1107 ◽  
Author(s):  
Meng-Jung Tsai ◽  
Jheng-Hua Luo ◽  
Jing-Yun Wu

A rhombus (4,4) grid showing two-fold 2D + 2D → 2D interweaved nets appeared to be a good adsorbent to selectively adsorb and separate anionic methyl orange (MO) and acid orange 7 (AO7) dyes over cationic methylene blue (MB) and malachite green (MG) from water with high adsorption capacities in both darkness and daylight.

2018 ◽  
Vol 2 (9) ◽  
pp. 1664-1673 ◽  
Author(s):  
Thangavel Selvamani ◽  
Sambandam Anandan ◽  
Luis Granone ◽  
Detlef W. Bahnemann ◽  
Muthupandian Ashokkumar

Bismuth oxide polymorphs (β-Bi2O3 nanoparticles and α-Bi2O3 coral-like morphology) were synthesized and they show an enhanced efficacy for the degradation of rhodamine B and acid orange 7 as compared to that of methylene blue and methyl orange under simulated solar illumination.


Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 208
Author(s):  
Ramona B. J. Ihlenburg ◽  
Anne-Catherine Lehnen ◽  
Joachim Koetz ◽  
Andreas Taubert

New cryogels for selective dye removal from aqueous solution were prepared by free radical polymerization from the highly water-soluble crosslinker N,N,N’,N’-tetramethyl-N,N’-bis(2-ethylmethacrylate)-propyl-1,3-diammonium dibromide and the sulfobetaine monomer 2-(N-3-sulfopropyl-N,N-dimethyl ammonium)ethyl methacrylate. The resulting white and opaque cryogels have micrometer sized pores with a smaller substructure. They adsorb methyl orange (MO) but not methylene blue (MB) from aqueous solution. Mixtures of MO and MB can be separated through selective adsorption of the MO to the cryogels while the MB remains in solution. The resulting cryogels are thus candidates for the removal of hazardous organic substances, as exemplified by MO and MB, from water. Clearly, it is possible that the cryogels are also potentially interesting for removal of other compounds such as pharmaceuticals or pesticides, but this must be investigated further.


2013 ◽  
Vol 330 ◽  
pp. 112-116 ◽  
Author(s):  
Nabilah A. Lutpi ◽  
N. Najihah Jamil ◽  
C.K. Kairulazam C.K. Abdullah ◽  
Yee Shian Wong ◽  
Soon An Ong ◽  
...  

The adsorption of Methylene Blue (MB) and Acid Orange 7 (AO7) dye onto Ananas Comosus Mixed Peels and Leaves (ACMPL) were carried out by conducting four different parameters such as initial concentration, pH, dosage of adsorbent, and contact time. Effect of initial concentration for both dyes showed that higher initial concentration would take longer contact time to attain equilibrium due to higher amount of adsorbate molecules. The effect of pH showed highest percentage removal for MB is at pH 9 which is 95.81%. Meanwhile for AO7 the highest percentage removal is 31.06% at pH 3. The percentage removal of MB had reached the equilibrium at dosage 0.5g while AO7 keep increasing with the increment of adsorbent dosage. The percentage removal of MB and AO7 had increased until hour 2.5 which was from 72.5% to 86.93% and 19.441% to 36.89% respectively and reached equilibrium at 3 hour contact time.


2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Feng Zhang ◽  
Yue Yin ◽  
Chunlei Qiao ◽  
Ya-nan Luan ◽  
Mengyan Guo ◽  
...  

In this study, polypyrrole-modified red mud (PRM) was prepared for the efficient removal of anionic dyes (methyl orange and Congo red) from aqueous solutions. The phytotoxicity (bean sprouts) of the dye solution before and after dye removal was investigated. Adsorption kinetics confirmed that the adsorption of methyl orange (MO) and Congo red (CR) on PRM was controlled by chemical reactions between the functional groups of polypyrrole and dyes. From Langmuir isotherm fitting, we found the theoretical adsorption capacities of MO and CR on PRM were 194.1 and 314.9 mg/g, respectively. The adsorption progress of MO and CR on PRM was found to be spontaneous and endothermic. The column studies demonstrated that, under dynamic flow, the PRM can efficiently remove MO and CR from aqueous solution, with adsorption capacities of 31.08 and 55.04 mg/g, respectively. In the toxicity test, the phytotoxicity of the column effluents (after dye removal) was significantly lowered compared to the initial dye influents. After the removal of MO and CR, the average root length of bean sprouts was increased from 3.30 cm to 5.18 cm and from 3.01 cm to 7.00 cm, respectively. These findings highlighted the efficient removal of dyes by PRM from aqueous solution, demonstrating the possible application of PRM for the removal of dye from dye-contaminated wastewaters.


2013 ◽  
Vol 10 (1) ◽  
pp. 16-23 ◽  

C.I. Acid Orange 7 (AO7) commonly used as a textile dye and could be degraded by UV/ZnO, UV/H2O2 and UV/H2O2/Fe (III) (photofenton) processes. In the photocatalytic degradation of dye by UV/ZnO process, effect of some parameters such as UV irradiation time, presence of ZnO and UV irradiation, pH, concentrations of ZnO, dye, H2O2 and ethanol was examined and first order reaction rate constant was calculated equal to 2.39×10-2 min-1 at experimental condition. The semi-log plot of dye concentration versus time was linear, suggesting first order reaction. Efficiency of photodegradation process in the absence of ZnO photocatalyst and UV light was small. Increasing the UV irradiation time increased AO7 removal. Ethanol had inhibitory effect on this process. Maximum AO7 removal was seen at neutral pH area. In the UV/H2O2 process, effect of some parameters such as presence of H2O2 and UV irradiation, amount of H2O2, effect of pH and addition of bicarbonate on the efficiency of dye removal were examined. Absence of each of UV irradiation or H2O2 decreased AO7 removal efficiency near to zero. Increasing H2O2 concentration increased dye removal to some extent but at higher H2O2 concentrations, dye removal efficiency did not increase. Increasing pH to value about 9 increased the AO7 removal efficiency and increasing bicarbonate anion concentration decreased it. Rate constant of AO7 removal by this process was calculated to be equal to 4.221×10-1 min-1 at experimental condition. Also, the order of UV/ H2O2/Fe (III) > UV/ H2O2 > UV/Fe (III) > H2O2/Fe (III), was seen for AO7 removal efficiency of these processes. Increasing Fe (III) and oxalate concentration increased dye removal efficiency.


2020 ◽  
Vol 81 (6) ◽  
pp. 1180-1190
Author(s):  
You Wang ◽  
Qifan Peng ◽  
Naseem Akhtar ◽  
Xiaonong Chen ◽  
Yaqin Huang

Abstract Microporous fish waste-based activated carbon material (MFC) was prepared, with a large surface area of 2,193.52 m²/g, a pore size of 2.67 nm and micropore and total pore volumes of 0.9168 cm³/g and 0.9975 cm³/g, respectively. Adsorption efficiency of MFC was investigated by removal of methylene blue dye from wastewater. The Langmuir model and pseudo-second-order kinetics adequately described the adsorption process. MFC exhibited a high adsorption capacity of 476.19 mg/g at 30 °C, and reached equilibrium within 1 h. MFC could be an efficient and low-cost adsorbent for cationic dye removal during wastewater treatment.


2006 ◽  
Vol 53 (11) ◽  
pp. 163-171 ◽  
Author(s):  
N. Yemashova ◽  
S. Kalyuzhnyi

Four selected azo dyes (acid orange 6, acid orange 7, methyl orange and methyl red) were completely decolourised in the presence of anaerobic granular sludge, while only methyl red was degraded in aerobic conditions using a conventional activated sludge. Additional experiments with culture broth devoid of cells showed that anaerobic decolourisation of azo dyes was performed by extracellular reducing agents produced by anaerobic bacteria. This was further confirmed by abiotic experiments with sulphide and NADH. The presence of redox mediators such as riboflavin led to dramatic acceleration of the anaerobic biodecolourisation process. The azo dye reduction products were found to be sulphanilic acid and 4-aminoresorcinol for acid orange 6; sulphanilic acid and 1-amino-2-naphthol for acid orange 7; N,N-dimethyl-1,4-phenylenediamine and sulphanilic acid for methyl orange; and N,N-dimethyl-1,4-phenylenediamine and anthranilic acid for methyl red. Anaerobic toxicity assays showed that the azo dyes were more toxic than their breakdown products (aromatic amines), except 1-amino-2-naphthol. In the presence of activated sludge, only anthranilic acid was completely mineralised while sulphanilic acid was persistent. 4-aminoresorcinol, 1-amino-2-naphthol and N,N-dimethyl-1,4-phenylenediamine underwent autooxidation in aerobic conditions yielding coloured polymeric products. On the contrary, in the presence of granular methanogenic sludge, 4-aminoresorcinol, 1-amino-2-naphthol and anthranilic acid were quantitatively methanised, sulphanilic acid was partially (70%) mineralised while N,N-dimethyl-1,4-phenylenediamine was only demethylated producing 1,4-phenylenediamine as an end product.


2019 ◽  
Vol 6 (3) ◽  
pp. 157-170
Author(s):  
Amirreza Talaiekhozani ◽  
Abbas Heydari Chaleshtori ◽  
Farhad Banisharif ◽  
Zeinab Eskandari ◽  
Mohammad Nasiri ◽  
...  

Background: Industrial dyes are toxic and carcinogenic, therefore, they should be removed from wastewater. The aim of this study was to investigate the removal of acid orange 7 Dye from wastewater using ultraviolet (UV) radiation, MgO nanoparticles, ultrasonic method alone and in combination with each other. Methods: The effects of some factors such as temperature, pH, hydraulic retention time (HRT), UV power, and concentration of MgO nanoparticles on the removal of Acid Orange 7 dye from synthetic wastewater using different methods were investigated. Also, adsorption isotherms for MgO nanoparticles and kinetics for UV radiation were investigated. Results: The optimum HRT was 55 minutes while the temperature was not effective in dye removal using the ultrasonic method. Under optimum conditions for UV irradiation method (HRT = 70 minutes, UV power = 170 mW/cm2, and temperature = 10˚C), 58% of the dye was removed. However, under optimum conditions for MgO nanoparticles method (HRT = 15 minutes, temperature = 20˚C, and ratio of MgO nanoparticles to the initial dye concentration = 67.2), 82% of the dye was removed. By combining these methods, the dye removal efficiency was significantly increased. The combination of ultrasonic method and MgO nanoparticles had no significant effect on increasing the dye removal efficiency from wastewater. It was revealed that dye removal using UV radiation can be described by the first-order kinetics. Conclusion: According to the results, UV radiation has a synergistic effect on the dye adsorption process by MgO nanoparticles. Therefore, the combination of these methods can be effective for the removal of dye from wastewater.


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