Synergic and competitive adsorption of Li–Na–MgCl2 onto lithium–aluminum hydroxides

Adsorption ◽  
2020 ◽  
Vol 26 (7) ◽  
pp. 1039-1049
Author(s):  
Huixiong Jiang ◽  
Shuiyi Zhang ◽  
Ying Yang ◽  
Jianguo Yu
2019 ◽  
Vol 98 (2) ◽  
pp. 544-555 ◽  
Author(s):  
Huixiong Jiang ◽  
Ying Yang ◽  
Shuying Sun ◽  
Jianguo Yu

Author(s):  
E. Bischoff ◽  
O. Sbaizero

Fiber or whisker reinforced ceramics show improved toughness and strength. Bridging by intact fibers in the crack wake and fiber pull-out after failure contribute to the additional toughness. These processes are strongly influenced by the sliding and debonding resistance of the interfacial region. The present study examines the interface in a laminated 0/90 composite consisting of SiC (Nicalon) fibers in a lithium-aluminum-silicate (LAS) glass-ceramic matrix. The material shows systematic changes in sliding resistance upon heat treatment.As-processed samples were annealed in air at 800 °C for 2, 4, 8, 16 and 100 h, and for comparison, in helium at 800 °C for 4 h. TEM specimen preparation of as processed and annealed material was performed with special care by cutting along directions having the fibers normal and parallel to the section plane, ultrasonic drilling, dimpling to 100 pm and final ionthinning. The specimen were lightly coated with Carbon and examined in an analytical TEM operated at 200 kV.


2014 ◽  
Vol 13 (10) ◽  
pp. 2583-2592 ◽  
Author(s):  
Beenish Saba ◽  
Audil Rashid ◽  
Tariq Mahmood ◽  
Faisal Mehmood ◽  
Azeem Khalid ◽  
...  

Author(s):  
A.M. Semiletov ◽  
◽  
Yu.B. Makarychev ◽  
A.A. Chirkunov ◽  
L.P. Kazansky ◽  
...  

The application of mixed corrosion inhibitor (CI), which is an equimolar composition of oleoyl sarcosinate (SOS) and sodium flufenamate (SFF), for protection of D16 aluminum alloy from atmospheric corrosion has been studied. The polarization measurements used to assess the effectiveness of preliminary passivation of the alloy with solutions of SOS, SFF and their composition showed significant advantages of mixed CI. The XPS method was used to study features of CI adsorption on the surface of D16 alloy. It has been established that upon adsorption of SOS and SFF separately a monolayer is formed, firmly bonded to the alloy surface, thickness of which is not exceeding 2.6—3.2 nm. After the joint adsorption of these CI, the layer thickness reaches 12—20 nm. The composition of this layer includes a considerable amount of Al3+ ions (~20%) related to their compounds with SFF and SOS, as well as to aluminum hydroxides. A possible mechanism for the formation of such a protective layer is proposed. The results of corrosion tests in a humid atmosphere with daily water condensation on samples of D16 alloy confirmed the high protective ability of the mixed CI film.


2019 ◽  
Author(s):  
Chem Int

Dodecyltrimethylammonium bromide (DTAB)–modified and unmodified calcium bentonite were both used for the competitive adsorption of aromatics (xylene, ethylbenzene and toluene) and petroleum products (gasoline, dual purpose kerosene and diesel) from their aqueous solution. Infrared spectroscopy (IR) and expansion tests (adsorption capacity and Foster swelling) measurement were performed in order to evaluate the performance of the adsorbents. The Foster swelling index and adsorption capacity of the DTAB modified calcium bentonite in the organic solvents follow the trend: xylene > ethylbenzene > toluene > gasoline > dual purpose kerosene (DPK) > diesel > water. However, the adsorption capacity of the adsorbent in diesel outweighed the adsorption capacity in DPK at high concentration of DTAB indicating that diesel has higher affinity for high DTAB concentration than DPK. The percentage removal of the solvent is directly proportional to the concentration of DTAB used in modifying the bentonite as well as the contact time between the adsorbent and the solvent, hence modified calcium bentonite adsorbed a higher percentage of organic solvents than the unmodified calcium bentonite. The adsorption characteristics of both adsorbents improved remarkably after proper agitation of the organic solvents, the unmodified calcium bentonite however adsorbed more water than the modified bentonite. Data obtained from adsorption isotherm models confirms that Freundlich adsorption isotherm model was favored more than Langmuir adsorption isotherm model with the correlation factor (R2) of the former tending more towards unity. The adsorption of ethylbenzene using DTAB modified and unmodified calcium bentonites follow a pseudo second order kinetics mechanism, suggesting that the rate determining step of adsorption involves both the adsorbent and the organic solvent.


2017 ◽  
Vol 13 (6) ◽  
Author(s):  
Linshan Wang ◽  
Cholhwan Kim ◽  
Xinyue Zhang ◽  
Carlos Fernandez ◽  
Ting Sun ◽  
...  

Author(s):  
Joshua O. Ighalo ◽  
Lois T. Arowoyele ◽  
Samuel Ogunniyi ◽  
Comfort A. Adeyanju ◽  
Folasade M. Oladipo-Emmanuel ◽  
...  

Background: The presence of pollutants in polluted water is not singularized hence pollutant species are constantly in competition for active sites during the adsorption process. A key advantage of competitive adsorption studies is that it informs on the adsorbent performance in real water treatment applications. Objective: This study aims to investigate the competitive adsorption of Pb(II), Cu(II), Fe(II) and Zn(II) using elephant grass (Pennisetum purpureum) biochar and hybrid biochar from LDPE. Method: The produced biochar was characterised by Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). The effect of adsorption parameters, equilibrium isotherm modelling and parametric studies were conducted based on data from the batch adsorption experiments. Results: For both adsorbents, the removal efficiency was >99% over the domain of the entire investigation for dosage and contact time suggesting that they are very efficient for removing multiple heavy metals from aqueous media. It was observed that removal efficiency was optimal at 2 g/l dosage and contact time of 20 minutes for both adsorbent types. The Elovich isotherm and the pseudo-second order kinetic models were best-fit for the competitive adsorption process. Conclusion: The study was able to successfully reveal that biomass biochar from elephant grass and hybrid biochar from LDPE can be used as effective adsorbent material for the removal of heavy metals from aqueous media. This study bears a positive implication for environmental protection and solid waste management.


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