scholarly journals Adsorption Mechanism of High-Concentration of Ammonium onto Chinese Natural Zeolite by Experimental Optimization and Theoretical Computation

2021 ◽  
Author(s):  
Pan Liu ◽  
Yongjun Liu ◽  
Aining Zhang ◽  
Zhe Liu ◽  
Xingshe Liu ◽  
...  
Keyword(s):  
Natural Zeolite ◽  
Adsorption Mechanism ◽  
Low Cost ◽  
Metal Cations ◽  
Exchange Capacity ◽  
Dynamics Simulation ◽  
Bulk Solution ◽  
Wastewater Remediation ◽  
High Concentration ◽  
Experimental Optimization

Abstract Background Natural zeolite, abundant hierarchically porous structure aluminosilicate mineral, have high affinity to ammonium in solution. A considerable amount of literature has been published on the removal of ammonium in waters by zeolite, but mainly focused on the low-content and even trace ammonium. Few literatures were reported about the natural zeolite as adsorbent to remove high-level of ammonium in coal chemical wastewater. Therefore, adsorption mechanism of high-concentration ammonium in aqueous solution using Chinese natural zeolite was disclosed by the strategy of experimental optimization combining with Molecular Dynamics simulation. ResultsThe natural zeolite presented unique adsorption performances for high- ammonium distinguish from that of low ammonium, which were characterized as exhibiting faster adsorption rate, greater loading capacity and apparent desorption. The hybrid physical-chemical adsorption as the mechanism was induced from the adsorption kinetics and isotherm study in 4000 mg-N/L solution. Besides to the electrostatic attraction between the framework and guest ammonium exchanged by metal cations in the zeolite framework, the existence of the chemical bonding and hydrogen bonding forces was supported experimentally from the ion exchange capacity (IEC) investigation by the great disequilibrium between the total exchanged metal cations and ammonium. Moreover, the above were confirmed theoretically by the calculated results in the perspective of bonding strength in MD simulation. Considering comprehensively, we concluded physisorption dominated the initial adsorption stage as multilayer adsorption and chemisorption governed the subsequent adsorption process as monolayer form. Besides, the putative explanation for the desorption-occurrence was given that most ammonium concentrated in the channel openings physically, and transferred into the bulk solution preferentially through the mesopores and macropores. Conclusions Overall, we have demonstrated that the Chinese natural zeolite had the potential to capture high-concentration ammonium in wastewater remediation effectively. Considering with several research thinking comprehensively, this investigation enriched the adsorption mechanism research, and provided a novel insight for designing a workable approach for rapidly alleviating subsequent water decontamination processes using low-cost abundant minerals.

scholarly journals Organobentonites as multifunctional adsorbents of organic and inorganic water pollutants

2014 ◽  
Vol 79 (2) ◽  
pp. 253-263 ◽  
Author(s):  
Natаsa Jovic-Jovicic ◽  
Aleksandra Milutinovic-Nikolic ◽  
Marija Zunic ◽  
Zorica Mojovic ◽  
Predrag Bankovic ◽  
...  
Keyword(s):  
Low Cost ◽  
Dye Adsorption ◽  
Toxic Metal ◽  
Bentonite Clay ◽  
Metal Cations ◽  
Exchange Capacity ◽  
Inorganic Pollutants ◽  
Water Pollutants ◽  
Component Solution ◽  
Efficient Adsorbent

The aim of this study was to find a low cost, easy to synthesize and efficient adsorbent for the simultaneous adsorption of both organic and inorganic pollutants (including textile dyes, toxic metals etc.). The starting material, domestic bentonite clay from Bogovina was modified with amounts of hexadecyltrimethylammonium cations corresponding to 0.5 and 1.0 times of the value of the cation exchange capacity value. The organobentonites were tested as adsorbents in a three-dye-containing solution, a three-component solution of Pb2+, Cd2+ and Ni2+ and a hexa- component solution containing all investigated dyes and toxic metal cations. The used adsorbents showed the highest affinity toward Acid Yellow 99 and Ni2+ ions. Dye adsorption was enhanced in the presence of toxic metal cations, while the adsorption of all toxic cations from the hexa-component solution was lower than from the three-component solution containing only toxic cations. The synthesized hexadecyltrimethylammonium bentonite could be regarded as an efficient multifunctional adsorbent for the investigated type of water pollutants.

Improved photocatalytic conversion of high−concentration ammonia in water by low−cost Cu/TiO2 and its mechanism study

Chemosphere ◽  
2021 ◽  
Vol 274 ◽  
pp. 129689
Author(s):  
Jianpei Feng ◽  
Xiaolei Zhang ◽  
Guan Zhang ◽  
Ji Li ◽  
Wei Song ◽  
...  
Keyword(s):  
Low Cost ◽  
Mechanism Study ◽  
High Concentration

scholarly journals Synthesis of poly (n-butyl acrylate) with tempo by nitroxide mediated polymerization method

2021 ◽  
pp. 096739112110245
Author(s):  
Amrita Sharma ◽  
PP Pande
Keyword(s):  
Butyl Acrylate ◽  
Low Cost ◽  
Polymerization Process ◽  
Polymerization Reaction ◽  
High Concentration ◽  
Acrylate Monomer ◽  
Controlled Polymerization ◽  
Acrylate Monomers ◽  
Nitroxide Mediated Polymerization ◽  
Polymerization Method

It has been observed that acrylate monomers are very difficult to polymerize with the low cost nitroxide catalyst 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO). Therefore, costly acyclic nitroxides such as N-tert-butyl-N-(1-diethylphosphono-2,2-dimethyl)-N-oxyl, (SG1), 2,2,5-Trimethyl-4-phenyl-3-azahexane-3-nitroxide (TIPNO) and TIPNO derivatives have to be used for the polymerization of the acrylic acid derivatives. There are very few reports on the use of TEMPO-derivatives toward the polymerization of n-butyl acrylate. Generally different reducing agents viz. glucose, ascorbic acid, hydroxyacetone etc. have been used to destroy excess TEMPO during the polymerization reaction. The acrylate polymerizations fail in the presence of TEMPO due to the strong C–O bond formed between the acrylate chain end and nitroxide. To the best of our knowledge, no literature report is available on the use of TEMPO without reducing agent or high temperature initiators, toward the polymerization of n-butyl acrylate. The present study has been carried out with a view to re-examine the application of low cost nitroxide TEMPO, so that it can be utilized towards the polymerization of acrylate monomers (e.g. n-butyl acrylate). We have been able to polymerize n-butyl acrylate using the nitroxide TEMPO as initiator (via a macroinitiator). In this synthesis, a polystyrene macroinitiator was synthesized in the first step from TEMPO, after this TEMPO end-capped styrene macroinitiator (PSt-TEMPO) is used to polymerize n-butyl acrylate monomer. The amount of macroinitiator taken was varied from 0.05% to 50% by weight of n-butyl acrylate monomer. The polymerization was carried out at 120°C by bulk polymerization method. The experimental findings showed a gradual increase in molecular weight of the polymer formed and decrease in the polydispersity index (PDI) with increase in amount of PSt-TEMPO macroinitiator taken. In all experiments conversion was more than 80%. These results indicate that the polymerization takes place through controlled polymerization process. Effect of different solvents on polymerization has also been investigated. In the following experiments TEMPO capped styrene has been used as macroinitiator leading to the successful synthesis of poly n-Butyl acrylate. It has been found that styrene macroinitiator is highly efficient for the nitroxide mediated polymerization, even in very small concentration for the synthesis of poly n-butyl acrylate. High concentration of macroinitiator results in the formation of block copolymers of polystyrene and poly ( n-butyl acrylate) viz. polystyrene-block-poly-( n-butyl acrylate). The use of TEMPO toward controlled polymerization is of much importance, because it is the nitroxide commercially available at the lowest cost.

scholarly journals Innovative Polymeric Hybrid Nanocomposites for Application in Photocatalysis

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1184
Author(s):  
Maria Cantarella ◽  
Giuliana Impellizzeri ◽  
Alessandro Di Mauro ◽  
Vittorio Privitera ◽  
Sabrina Carola Carroccio
Keyword(s):  
Hybrid Systems ◽  
Hybrid Materials ◽  
Large Scale ◽  
Mechanical Stability ◽  
Low Cost ◽  
Atomic Layer ◽  
Hybrid Nanocomposites ◽  
Polymeric Nanocomposites ◽  
Wastewater Remediation ◽  
Antibacterial Performance

The immobilization of inorganic nanomaterials on polymeric substrates has been drawing a lot of attention in recent years owing to the extraordinary properties of the as-obtained materials. The hybrid materials, indeed, combine the benefits of the plastic matter such as flexibility, low-cost, mechanical stability and high durability, with them deriving from their inorganic counterparts. In particular, if the inorganic fillers are nanostructured photocatalysts, the originated hybrid systems will be able to utilize the energy delivered by light, catalysing chemical reactions in a sustainable pathway. Most importantly, since the nanofillers can be ad-hoc anchored to the macromolecular structure, their release in the environment will be prevented, thus overcoming one of the main restrictions that impedes their applications on a large scale. In this review, several typologies of hybrid photocatalytic nanomaterials, obtained by using both organic and inorganic semiconductors and realized with different synthetic protocols, were reported and discussed. In the first part of the manuscript, nanocomposites realized by simply blending the TiO2 or ZnO nanomaterials in thermoplastic polymeric matrices are illustrated. Subsequently, the atomic layer deposition (ALD) technique is presented as an excellent method to formulate polymeric nanocomposites. Successively, some examples of polyporphyrins hybrid systems containing graphene, acting as photocatalysts under visible light irradiation, are discussed. Lastly, photocatalytic polymeric nanosponges, with extraordinary adsorption properties, are shown. All the described materials were deeply characterized and their photocatalytic abilities were evaluated by the degradation of several organic water pollutants such as dyes, phenol, pesticides, drugs, and personal care products. The antibacterial performance was also evaluated for selected systems. The relevance of the obtained results is widely overviewed, opening the route for the application of such multifunctional photocatalytic hybrid materials in wastewater remediation.

scholarly journals Molecular Dynamics Simulation of the Influence of RDX Internal Defects on Sensitivity

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 329
Author(s):  
Pengmin Yan ◽  
Xue Zhao ◽  
Jiuhou Rui ◽  
Juan Zhao ◽  
Min Xu ◽  
...  
Keyword(s):  
Energetic Materials ◽  
Low Cost ◽  
Relative Sensitivity ◽  
Dynamics Simulation ◽  
Safety Properties ◽  
Internal Defects ◽  
X Ray ◽  
X Ray Computed ◽  
Low Sensitivity ◽  
Higher Sensitivity

The internal defect is an important factor that could influence the energy and safety properties of energetic materials. RDX samples of two qualities were characterized and simulated to reveal the influence of different defects on sensitivity. The internal defects were characterized with optical microscopy, Raman spectroscopy and microfocus X-ray computed tomography technology. The results show that high-density RDX has fewer defects and a more uniform distribution. Based on the characterization results, defect models with different defect rates and distribution were established. The simulation results show that the models with fewer internal defects lead to shorter N-NO2 maximum bond lengths and greater cohesive energy density (CED). The maximum bond length and CED can be used as the criterion for the relative sensitivity of RDX, and therefore defect models doped with different solvents are established. The results show that the models doped with propylene carbonate and acetone lead to higher sensitivity. This may help to select the solvent to prepare low-sensitivity RDX. The results reported in this paper are aiming at the development of a more convenient and low-cost method for studying the influence of internal defects on the sensitivity of energetic materials.

Design and operation of a tripod walking robot via dynamics simulation

Robotica ◽  
2010 ◽  
Vol 29 (5) ◽  
pp. 733-743 ◽  
Author(s):  
Conghui Liang ◽  
Hao Gu ◽  
Marco Ceccarelli ◽  
Giuseppe Carbone
Keyword(s):  
Mechanical Design ◽  
Low Cost ◽  
Three Dimensional ◽  
The Body ◽  
Dynamics Simulation ◽  
Walking Ability ◽  
Walking Robot ◽  
Three Dimensional Model ◽  
Software Environment ◽  
Leg Mechanisms

SUMMARYA mechanical design and dynamics walking simulation of a novel tripod walking robot are presented in this paper. The tripod walking robot consists of three 1-degree-of-freedom (DOF) Chebyshev–Pantograph leg mechanisms with linkage architecture. A balancing mechanism is mounted on the body of the tripod walking robot to adjust its center of gravity (COG) during walking for balancing purpose. A statically stable tripod walking gait is performed by synchronizing the motions of the three leg mechanisms and the balancing mechanism. A three-dimensional model has been elaborated in SolidWorks® engineering software environment for a characterization of a feasible mechanical design. Dynamics simulation has been carried out in the MSC.ADAMS® environment with the aim to characterize and to evaluate the dynamic walking performances of the proposed design with low-cost easy-operation features. Simulation results show that the proposed tripod walking robot with proper input torques, gives limited reaction forces at the linkage joints, and a practical feasible walking ability on a flatten ground.

scholarly journals Ion exchange resin selection for concentration and purification of uranium leached by sulphuric acid solution

2015 ◽  
Vol 5 (2) ◽  
pp. 33-38
Author(s):  
Quang Thai Le ◽  
Minh Tuan Pham ◽  
Nguyen Quynh Trinh ◽  
Khac Tuan Vu ◽  
Hong Ha Nguyen ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Low Cost ◽  
Acid Leaching ◽  
Ion Exchange Resin ◽  
Exchange Capacity ◽  
High Price ◽  
Strong Base ◽  
Total Exchange Capacity ◽  
Total Exchange ◽  
Uranium Solution

Ion exchange is one of the most popular techniques for recovery and purification of uranium from sulfuric acid leaching solution, especially for recovery of uranium from a low uranium containing solutions. Resins commonly used are strong base or weak base anion resins with amine functional group. The anionic form of resins may be NO3-, Cl- , SO­42- or OH-. The selection of  a resin depends on the uranium total exchange capacity, selectivity and the cost. The previous studies often use Amberlite IRA-420 for concentration and purification of uranium solution from Pa Lua sandstone ores. This is a good and suitable resin but high price. To diversify the resins and reduce the costs, instead of IRA-420, the authors tested two commercial resins Indion GS300 (India) and Purolite A400 (UK) in the processing of uranium solution from sandstone ores. The results showed that the uranium total exchange capacity of  these resins is only about 80 - 85% over  Amberlite IRA-420, but these resins should be able to be used instead of Amberlite IRA-420 due to their low cost and availability in Vietnam.

scholarly journals Removal of Orange G Dye from Aqueous Solution by Adsorption: A Short Review

2020 ◽  
Vol 9 (1) ◽  
pp. 318-327
Keyword(s):  
Aqueous Solution ◽  
Activated Carbon ◽  
Low Cost ◽  
Short Review ◽  
Industrial Wastes ◽  
Present Review ◽  
Wastewater Remediation ◽  
Experimental Conditions ◽  
Adsorption Capacities ◽  
Orange G

Adsorption is a widely used technique for wastewater remediation. The process is effective and economical for the removal of various pollutants from wastewater, including dyes. Moreover, Besides commercial activated carbon, different low-cost materials such as agricultural and industrial wastes are now used as adsorbents. The present review focused on the removal of a teratogenic and carcinogenic dye, orange G (OG) via adsorption using several adsorbents, together with the experimental conditions and their adsorption capacities. Based on the information compiled, various adsorbents have shown promising potential for OG removal.

scholarly journals REDUCTION OF METAL CATIONS CONTENT FROM THE AQUEOUS SOLUTIONS BY SORBENTS

2021 ◽  
Vol 2021 (6) ◽  
pp. 5307-5311
Author(s):  
IVETA PANDOVA ◽  
◽  
MIROSLAV RIMAR ◽  
Keyword(s):  
Heavy Metals ◽  
Aqueous Solutions ◽  
Natural Zeolite ◽  
Metal Cations ◽  
Sorption Kinetics ◽  
Synthetic Zeolite ◽  
Natural Zeolites ◽  
Chemically Treated ◽  
Synthetic Zeolites

The article presents the results of research on reducing the concentration of heavy metals, such as copper and nickel, on natural zeolite in comparison with synthetic zeolite and chemically treated natural zeolite. The reduction of the content of specific types of heavy metals from aqueous solutions was investigated by the method of sorption kinetics. The results indicate the ability of natural zeolites to compete with synthetic zeolites.

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