scholarly journals Structural Characteristics and Environmental Applications of Covalent Organic Frameworks

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2267
Author(s):  
Niaz Ali Khan ◽  
Muhammad Humayun ◽  
Muhammad Usman ◽  
Zahid Ali Ghazi ◽  
Abdul Naeem ◽  
...  
Keyword(s):  
Metal Ions ◽  
Structural Characteristics ◽  
Polymeric Materials ◽  
Environmental Applications ◽  
Covalent Organic Frameworks ◽  
Large Bank ◽  
Future Perspectives ◽  
Pore Sizes ◽  
Hazardous Metal ◽  
Separation Field

Covalent organic frameworks (COFs) are emerging crystalline polymeric materials with highly ordered intrinsic and uniform pores. Their synthesis involves reticular chemistry, which offers the freedom of choosing building precursors from a large bank with distinct geometries and functionalities. The pore sizes of COFs, as well as their geometry and functionalities, can be pre-designed, giving them an immense opportunity in various fields. In this mini-review, we will focus on the use of COFs in the removal of environmentally hazardous metal ions and chemicals through adsorption and separation. The review will introduce basic aspects of COFs and their advantages over other purification materials. Various fabrication strategies of COFs will be introduced in relation to the separation field. Finally, the challenges of COFs and their future perspectives in this field will be briefly outlined.

Stabilization of Hazardous Materials into Ferrites

1991 ◽  
Vol 23 (1-3) ◽  
pp. 399-404 ◽  
Author(s):  
Y. Tamaura ◽  
P. Q. Tu ◽  
S. Rojarayanont ◽  
H. Abe
Keyword(s):  
Aqueous Solution ◽  
Heavy Metal ◽  
Metal Ions ◽  
Present Method ◽  
Hazardous Materials ◽  
Precipitation Process ◽  
Waste Waters ◽  
Formation Reaction ◽  
Coating Method ◽  
Hazardous Metal

Stabilization of the hazardous materials by the Fe3O4-coating method was studied. In the ferrite-formation reaction in the aqueous solution, the adsorption of the metal ions and the oxidation of the adsorbed Fe(II) ions are repeated on the surface of the ferrite particles. This reaction was adopted to the coating of the hazardous materials with the Fe3O4(or ferrite). By repeating the two steps of l)the addition of the Fe(II) aqueous solution into the suspension of the hazardous materials, and 2)the oxidation by passing air through the reaction suspension, with the Fe3O4 layer, we could coat the surfaces of the hazardous materials, such as the heavy metal sludge from the neutralization-precipitation process, the CaF2 precipitates in the treatment of the waste waters containing fluoride ion along with hazardous metal ions, and the soils containing Cd(II) ion. These Fe3O4-coated hazardous materials are very stable and no heavy metal ions are leached under the normal environmental conditions. The ferrite sludges formed in the “Ferrite Process” were highly stabilized by the present method, and by the heat-treatment.

scholarly journals Recent Developments in Lignin- and Tannin-Based Non-Isocyanate Polyurethane Resins for Wood Adhesives—A Review

2021 ◽  
Vol 11 (9) ◽  
pp. 4242
Author(s):  
Manggar Arum Aristri ◽  
Muhammad Adly Rahandi Lubis ◽  
Sumit Manohar Yadav ◽  
Petar Antov ◽  
Antonios N. Papadopoulos ◽  
...  
Keyword(s):  
Automotive Industry ◽  
Polymeric Materials ◽  
Review Article ◽  
Future Perspectives ◽  
Wood Adhesives ◽  
Adhesion Properties ◽  
Lighting Industry ◽  
Renewable Natural Resources ◽  
Recent Developments ◽  
Strong Adhesion

This review article aims to summarize the potential of using renewable natural resources, such as lignin and tannin, in the preparation of NIPUs for wood adhesives. Polyurethanes (PUs) are extremely versatile polymeric materials, which have been widely used in numerous applications, e.g., packaging, footwear, construction, the automotive industry, the lighting industry, insulation panels, bedding, furniture, metallurgy, sealants, coatings, foams, and wood adhesives. The isocyanate-based PUs exhibit strong adhesion properties, excellent flexibility, and durability, but they lack renewability. Therefore, this study focused on the development of non-isocyanate polyurethane lignin and tannin resins for wood adhesives. PUs are commercially synthesized using polyols and polyisocyanates. Isocyanates are toxic, costly, and not renewable; thus, a search of suitable alternatives in the synthesis of polyurethane resins is needed. The reaction with diamine compounds could result in NIPUs based on lignin and tannin. The research on bio-based components for PU synthesis confirmed that they have good characteristics as an alternative for the petroleum-based adhesives. The advantages of improved strength, low curing temperatures, shorter pressing times, and isocyanate-free properties were demonstrated by lignin- and tannin-based NIPUs. The elimination of isocyanate, associated with environmental and human health hazards, NIPU synthesis, and its properties and applications, including wood adhesives, are reported comprehensively in this paper. The future perspectives of NIPUs’ production and application were also outlined.

Cellulose Based Electrospun Nanofilters: Perspectives On Tannery Effluent Waste Water Treatment

2021 ◽  
Author(s):  
Senthil Rethinam ◽  
Sardar Batıkan Kavukcu ◽  
Thiagarajan Hemalatha ◽  
A.Wilson Aruni ◽  
Aylin Sendemir
Keyword(s):  
Metal Ions ◽  
Waste Water Treatment ◽  
Toxic Metal ◽  
Poly Vinyl Alcohol ◽  
Tannery Effluent ◽  
Tea Leaves ◽  
Leather Industry ◽  
Elongation At Break ◽  
Hazardous Metal ◽  
Effluent Waste

Abstract Development of nanofilters with the capability to remove toxic metal ions from effluent wastewater will be of immense help to the leather industry. In this study, fibrous nanofilter (FNF) was prepared using micro cellulosic fiber (MCF) and tea leaves microparticles (TLM) blended in poly (vinyl) alcohol (PVA). FNF was analysed for its efficacy to remove hazardous metals from tannery effluent wastewater. The FNF had promising traits of tensile strength (19.24+0.05 Mpa), elongation at break (22.31+0.12 %), flexibility (10.88+0.05 %), water absorption (37.86+0.14 %) and desorption (32.54+0.33 %). The metal adsorption studies clearly reflected the removal of toxic Cr (VI) ions from the effluent water by FNF. The study establishes an economically feasible and highly efficient way to remove hazardous metal ions from effluent wastewater.

scholarly journals Molecularly Imprinted Polymers for Removal of Metal Ions: An Alternative Treatment Method

Biomimetics ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. 38 ◽  
Author(s):  
Özgecan Erdem ◽  
Yeşeren Saylan ◽  
Müge Andaç ◽  
Adil Denizli
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Membrane Filtration ◽  
Polymeric Materials ◽  
Treatment Method ◽  
Terrestrial Environment ◽  
Molecularly Imprinted ◽  
Metal Ion Removal ◽  
Ion Imprinted ◽  
Removal Of Metal Ions

Aquatic and terrestrial environment and human health have been seriously threatened with the release of metal-containing wastewater by the rapid growth in the industry. There are various methods which have been used for removal of ions from the environment, such as membrane filtration, ion exchange, membrane assisted liquid extraction and adsorption. As a sort of special innovation, a polymerization technique, namely molecular imprinting is carried out by specific identification for the target by mixing it with a functional monomer. After the polymerization occurred, the target ion can be removed with suitable methods. At the end of this process, specific cavities, namely binding sites, are able to recognize target ions selectively. However, the selectivity of the molecularly imprinted polymer is variable not only because of the type of ligand but also charge, size coordination number, and geometry of the target ion. In this review, metal ion-imprinted polymeric materials that can be applied for metal ion removal from different sources are discussed and exemplified briefly with different metal ions.

scholarly journals Research of nanostructural minerals – bentonites used in purification of mineral water from heavy metal ions (Cu2+, Pb2+, Cd2+, Zn 2+)

2020 ◽  
Vol 4 (78) ◽  
pp. 115-122
Author(s):  
A. SH. BUKUNOVA ◽  
◽  
G. ZH. TURSBEKOVA ◽  
L. B. IRISKINA ◽  
M. K. ZHAMANBAEVA ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Mine Water ◽  
Heavy Metal Ions ◽  
Structural Characteristics ◽  
Mining Industry ◽  
Bentonite Clay ◽  
Acid Activation ◽  
Exchange Cations ◽  
Aluminum Ions

This paper presents the results of studies on the use of bentonite from the Taganskoye field for purification of mine water from the mining industry from heavy metal ions (MI). It has been established that the use of the thermo-acid-activated form of bentonite clay allows the removal of MI Cu2+, Pb2+, Cd2+, Zn2+ions from mine water by 99.6, 94.7, 98.9, 99.5 %, respectively, which ensures that the maximum permissible concentration of fishery is achieved at selected optimal conditions that were identified on the basis of an active experiment. A comparative analysis of the presented results of mass spectrometry and scanning electron microscopy shows that they are valid and do not contradict the obtained experimental data on the composition of exchange cations and structural characteristics in ultrafine mineral phases of bentonite clay samples of natural and thermo-acid activated forms It has been established that during acid activation of bentonite clays, the structure of montmorillonite is retained upon extraction of up to 80 % of magnesium, iron, and aluminum ions and is destroyed only upon their almost complete extraction.

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