β-Cyclodextrin-Polyacrylamide Hydrogel for Removal of Organic Micropollutants from Water

Water pollution by various toxic substances remains a serious environmental problem, especially the occurrence of organic micropollutants including endocrine disruptors, pharmaceutical pollutants and naphthol pollutants. Adsorption process has been an effective method for pollutant removal in wastewater treatment. However, the thermal regeneration process for the most widely used activated carbon is costly and energy-consuming. Therefore, there has been an increasing need to develop alternative low-cost and effective adsorption materials for pollutant removal. Herein, β-cyclodextrin (β-CD), a cheap and versatile material, was modified with methacrylate groups by reacting with methacryloyl chloride, giving an average degree of substitution of 3 per β-CD molecule. β-CD-methacrylate, which could function as a crosslinker, was then copolymerized with acrylamide monomer via free-radical copolymerization to form β-CD-polyacrylamide (β-CD-PAAm) hydrogel. Interestingly, in the structure of the β-CD-PAAm hydrogel, β-CD is not only a functional unit binding pollutant molecules through inclusion complexation, but also a structural unit crosslinking PAAm leading to the formation of the hydrogel 3D networks. Morphological studies showed that β-CD-PAAm gel had larger pore size than the control PAAm gel, which was synthesized using conventional crosslinker instead of β-CD-methacrylate. This was consistent with the higher swelling ratio of β-CD-PAAm gel than that of PAAm gel (29.4 vs. 12.7). In the kinetic adsorption studies, phenolphthalein, a model dye, and bisphenol A, propranolol hydrochloride, and 2-naphthol were used as model pollutants from different classes. The adsorption data for β-CD-PAAm gel fitted well into the pseudo-second-order model. In addition, the thermodynamic studies revealed that β-CD-PAAm gel was able to effectively adsorb the different dye and pollutants at various concentrations, while the control PAAm gel had very low adsorption, confirming that the pollutant removal was due to the inclusion complexation between β-CD units and pollutant molecules. The adsorption isotherms of the different dye and pollutants by the β-CD-PAAm gel fitted well into the Langmuir model. Furthermore, the β-CD-PAAm gel could be easily recycled by soaking in methanol and reused without compromising its performance for five consecutive adsorption/desorption cycles. Therefore, the β-CD-PAAm gel, which combines the advantage of an easy-to-handle hydrogel platform and the effectiveness of adsorption by β-CD units, could be a promising pollutant removal system for wastewater treatment applications.

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The Role of Tourmaline Particles in the Moving Bed Bioreator for Coking Wastewater Treatment

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.321-324.192 ◽

2013 ◽

Vol 321-324 ◽

pp. 192-195

Author(s):

Jing Zhang

Keyword(s):

Wastewater Treatment ◽

Organic Contaminants ◽

Low Cost ◽

Oxygen Demand ◽

Pollutant Removal ◽

Coking Wastewater ◽

Excess Sludge ◽

Moving Bed ◽

Environmental Material

Tourmaline is a kind of natural low-cost mineral material. It has a number of unique physical properties and has been a kind of promising environmental material in wastewater treatment. This study was to investigate the aerobic biofilm treatment of coking wastewater with and without tourmaline addition. The results indicated that tourmaline added in moving bed bioreactor (MBBR) process could enhance the removal efficiency of chemical oxygen demand (COD).The organic contaminants could be removed by tourmaline added. The mechanisms of increase of organic contaminants removal may correlate to the existence of tourmaline spontaneous electrode. Micrograph of the excess sludge in the tourmaline-MBBR system indicated that the tourmaline added could be the carrier of the microbe and also affect the biomass and pollutant removal.

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Reduction of Organic and Inorganic Pollutant from Waste Water by Algae

International Letters of Natural Sciences ◽

10.18052/www.scipress.com/ilns.13.1 ◽

2014 ◽

Vol 13 ◽

pp. 1-8 ◽

Cited By ~ 6

Author(s):

Omprakash Sahu

Keyword(s):

Wastewater Treatment ◽

Conventional Treatment ◽

Low Cost ◽

Oxygen Demand ◽

Biological Oxygen Demand ◽

Biological Wastewater Treatment ◽

Toxic Substances ◽

Volatile Solid ◽

Inorganic Pollutant ◽

Wastewater Treatment Systems

Recently, algae have become significant organisms for biological purification of wastewater since they are able to accumulate plant nutrients, heavy metals, pesticides, organic and inorganic toxic substances and radioactive matters in their cells/bodies. Biological wastewater treatment systems with micro algae have particularly gained importance in last 50 years and it is now widely accepted that algal wastewater treatment systems are as effective as conventional treatment systems. These specific features have made algal wastewaters treatment systems an significant low-cost alternatives to complex expensive treatment systems particularly for purification of municipal wastewaters. By this method 70 % of biological oxygen demand, 66 % of chemical oxygen demand, 71 % total nitrogen, 67 % of phosphorus, 54 % volatile solid and 51 % of dissolved solid was reduced

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Ways to Improve the Efficiency of ТіО2-based Photocatalysts (Review)

Фізика і хімія твердого тіла ◽

10.15330/pcss.21.2.300-311 ◽

2020 ◽

Vol 21 (2) ◽

pp. 300-311

Author(s):

I.F. Mironyuk ◽

L.M. Soltys ◽

T.R. Tatarchuk ◽

V.I. Tsinurchyn

Keyword(s):

Low Cost ◽

Pollutant Removal ◽

Visible Range ◽

Selective Absorption ◽

Toxic Substances ◽

Practical Application ◽

Additional Absorption ◽

Global Issue ◽

Absorption Of Light ◽

Large Width

Water and air pollutants pose a significant environmental problem worldwide and photocatalysis is one way to address this global issue. Photocatalytic degradation of toxic substances under the influence of visible electromagnetic radiation is widely used for wastewater treatment. The most promising method of pollutant removal is the use of photocatalysts based on titanium (IV) oxide, which are recognized as one of the most effective due to chemical resistance, non-toxicity and low cost. However, their practical application is limited by the rapid recombination of photogenerated charge carriers and the selective absorption of light in the UV region due to the large width of band gap. To solve this scientific and practical problem, it is necessary to modify the surface, for example, through metallic or nonmetallic doping, in order to increase its photocatalytic activity due to additional absorption in the visible range of the spectrum. This review presents an analysis of current research on ways to increase the efficiency of TiO2-based photocatalysts.

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Chromic Acid Etching of Polyethylene

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100070801 ◽

1973 ◽

Vol 31 ◽

pp. 72-73

Author(s):

J. D. Muzzy ◽

R. D. Hester ◽

J. L. Hubbard

Keyword(s):

Chromic Acid ◽

Low Cost ◽

Acid Etching ◽

Crystalline Morphology ◽

Bulk Specimen ◽

Morphological Studies ◽

Perfect Form ◽

Molecular Length ◽

Lamellar Texture ◽

Cost Studies

Polyethylene is one of the most important plastics produced today because of its good physical properties, ease of fabrication and low cost. Studies to improve the properties of polyethylene are leading to an understanding of its crystalline morphology. Polyethylene crystallized by evaporation from dilute solutions consists of thin crystals called lamellae. The polyethylene molecules are parallel to the thickness of the lamellae and are folded since the thickness of the lamellae is much less than the molecular length. This lamellar texture persists in less perfect form in polyethylene crystallized from the melt.Morphological studies of melt crystallized polyethylene have been limited due to the difficulty of isolating the microstructure from the bulk specimen without destroying or deforming it.

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Novel Self-Healing Metallocopolymers with Pendent 4-Phenyl-2,2′:6′,2″-terpyridine Ligand: Kinetic Studies and Mechanical Properties

Polymers ◽

10.3390/polym13111760 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1760

Author(s):

Rose K. Baimuratova ◽

Gulzhian I. Dzhardimalieva ◽

Evgeniy V. Vaganov ◽

Valentina A. Lesnichaya ◽

Gulsara D. Kugabaeva ◽

...

Keyword(s):

Critical Role ◽

Specific Effect ◽

Kinetic Studies ◽

Radical Copolymerization ◽

Self Healing ◽

Free Radical Copolymerization ◽

Polymer Hydrogels ◽

Close Proximity ◽

Metal Group ◽

Metal Polymer

We report here our successful attempt to obtain self-healing supramolecular hydrogels with new metal-containing monomers (MCMs) with pendent 4-phenyl-2,2′:6′,2″-terpyridine metal complexes as reversible moieties by free radical copolymerization of MCMs with vinyl monomers, such as acrylic acid and acrylamide. The resulting metal-polymer hydrogels demonstrate a developed system of hydrogen, coordination and electron-complementary π–π stacking interactions, which play a critical role in achieving self-healing. Kinetic data show that the addition of a third metal-containing comonomer to the system decreases the initial polymerization rate, which is due to the specific effect of the metal group located in close proximity of the active center on the growth of radicals.

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Performance of Iron-Functionalized Activated Carbon Catalysts (Fe/AC-f) on CWPO Wastewater Treatment

Catalysts ◽

10.3390/catal11030337 ◽

2021 ◽

Vol 11 (3) ◽

pp. 337

Author(s):

Sara Mesa Medina ◽

Ana Rey ◽

Carlos Durán-Valle ◽

Ana Bahamonde ◽

Marisol Faraldos

Keyword(s):

Wastewater Treatment ◽

Activated Carbon ◽

Landfill Leachate ◽

Surface Composition ◽

Treatment Plant ◽

Reaction Medium ◽

Pollutant Removal ◽

Operating Conditions ◽

Water Matrix ◽

The Stability

Two commercial activated carbon were functionalized with nitric acid, sulfuric acid, and ethylenediamine to induce the modification of their surface functional groups and facilitate the stability of corresponding AC-supported iron catalysts (Fe/AC-f). Synthetized Fe/AC-f catalysts were characterized to determine bulk and surface composition (elemental analysis, emission spectroscopy, XPS), textural (N2 isotherms), and structural characteristics (XRD). All the Fe/AC-f catalysts were evaluated in the degradation of phenol in ultrapure water matrix by catalytic wet peroxide oxidation (CWPO). Complete pollutant removal at short reaction times (30–60 min) and high TOC reduction (XTOC = 80 % at ≤ 120 min) were always achieved at the conditions tested (500 mg·L−1 catalyst loading, 100 mg·L−1 phenol concentration, stoichiometric H2O2 dose, pH 3, 50 °C and 200 rpm), improving the results found with bare activated carbon supports. The lability of the interactions of iron with functionalized carbon support jeopardizes the stability of some catalysts. This fact could be associated to modifications of the induced surface chemistry after functionalization as a consequence of the iron immobilization procedure. The reusability was demonstrated by four consecutive CWPO cycles where the activity decreased from 1st to 3rd, to become recovered in the 4th run. Fe/AC-f catalysts were applied to treat two real water matrices: the effluent of a wastewater treatment plant with a membrane biological reactor (WWTP-MBR) and a landfill leachate, opening the opportunity to extend the use of these Fe/AC-f catalysts for complex wastewater matrices remediation. The degradation of phenol spiked WWTP-MBR effluent by CWPO using Fe/AC-f catalysts revealed pH of the reaction medium as a critical parameter to obtain complete elimination of the pollutant, only reached at pH 3. On the contrary, significant TOC removal, naturally found in complex landfill leachate, was obtained at natural pH 9 and half stoichiometric H2O2 dose. This highlights the importance of the water matrix in the optimization of the CWPO operating conditions.

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