Enhanced selectivity and capacity of clinoptilolite for Cd2+ removal from aqueous solutions by incorporation of magnetite nanoparticles and surface modification with cysteine

2016 ◽  
Vol 73 (9) ◽  
pp. 2284-2293 ◽  
Author(s):  
Masumeh Sharifi ◽  
Majid Baghdadi
Keyword(s):  
Surface Modification ◽  
Magnetite Nanoparticles ◽  
Weight Ratio ◽  
Correlation Coefficients ◽  
Effective Parameters ◽  
Equilibrium Data ◽  
Infrared Spectrometer ◽  
Modified Clinoptilolite ◽  
Enhanced Selectivity ◽  
Selectivity And Capacity

In this study, magnetic zeolite (MZ) nanocomposite modified with cysteine was developed in order to enhance selectivity and capacity of clinoptilolite for cadmium ion. The prepared MZ nanocomposite is containing clinoptilolite and magnetite nanoparticles with weight ratio of 3:1. The synthesized nanocomposite was characterized by transmission electron microscopy, X-ray diffraction and vibrating sample magnetometer. Surface modification was confirmed by Fourier transform infrared spectrometer. Experiments were carried out to find the optimum conditions for modification of clinoptilolite and to investigate the effective parameters (pH, adsorbent dosage, contact time, and temperature) on the adsorption of Cd2+ ion by modified clinoptilolite. The results showed enhanced selectivity of modified MZ in the presence of other naturally occurring cations (Na+, K+, Ca2+ and Mg2+) and ammonium. Kinetic and equilibrium data were well fitted by a pseudo second-order and Langmuir model, respectively, with high correlation coefficients. The maximum adsorption capacities of the modified and non-modified clinoptilolite were found to be 20.0 mg/g and 5.2 mg/g, respectively. Thermodynamic parameters revealed that the adsorption process is spontaneous and endothermic under studied conditions.

scholarly journals Adsorption of U(VI) from aqueous solution by Triocthylamine (TOA) functionalized magnetite nanoparticles as a novel adsorbent

2014 ◽  
Vol 10 (3) ◽  
pp. 2403-2414 ◽  
Author(s):  
Nemat Mansouri ◽  
Mohammad Noaparast ◽  
Kamal Saberyan
Keyword(s):  
Aqueous Solutions ◽  
Magnetite Nanoparticles ◽  
Adsorption Equilibrium ◽  
Weight Ratio ◽  
Chemical Separation ◽  
Initial Ph ◽  
Stirring Time ◽  
Equilibrium Data ◽  
Langmuir Isotherm Model ◽  
Adsorption Equilibrium Data

Adsorption of U (VI) from aqueous solutions was investigated using magnetically assisted chemical separation (MACS) process. In the present study, Triocthylamine (TOA) functionalized magnetite nanoparticles (TOAFMNPs) were applied as a novel adsorbent for adsorption of U (VI) from aqueous solutions. The effects of initial pH, Triocthylamine to magnetite nanoparticles weight ratio, amount of adsorbent, stirring time and initial U(VI) concentration on U(VI) adsorption efficiency were investigated by batch experiments. The adsorption of U(VI) using this adsorbent was pH dependent, and the optimal pH was 5.5. In kinetics studies, the adsorption equilibrium can be reach within 20 min., and the experimental data were well fitted by the pseudo-second-order model. The highest value of U(VI) adsorption (93.8%) was achieved in optimum conditions. The Langmuir isotherm model correlates well with the U(VI) adsorption equilibrium data for the concentration range 10-80 mg/l. The maximum U(VI) adsorption capacity onto adsorbent was 27.5 mg/g at room temperature. Present study suggests that TOAFMNPs could be employed as a potential adsorbent for U(VI) adsorption, and also could provide a simple and fast separation method for removal of U(VI) ion from solutions

Surface Modification of High Density Ceramic Powder for Increasing Suspension Capacity in Three-Dimensional Printing Application

2018 ◽  
Vol 936 ◽  
pp. 159-163 ◽  
Author(s):  
Huang Jan Hsu ◽  
Shyh Yuan Lee ◽  
Shinn Liang Chang ◽  
Cho Pei Jiang
Keyword(s):  
Surface Modification ◽  
Ball Milling ◽  
Ceramic Powder ◽  
Three Dimensional ◽  
Treatment Protocol ◽  
Weight Ratio ◽  
Average Diameter ◽  
Zirconia Powder ◽  
Three Dimensional Printing ◽  
Promising Tool

Three-dimensional slurry printing is a promising tool for making ceramic object but it limits in high dense ceramic powder because of poor suspension capacity. This study uses zirconia powder with an average diameter of 2 μm because its density is 5.67 g/cm3. A treatment protocol is proposed to improve the suspension capacity of zirconia powder including the ball milling, surface modification and resin blending. Experimental results show that adding 1% of isostearyl titanate, a coupling agent, for surface modification can enhance the lipophilicity of zirconia powder. Mixing surface modification powder in resin with a weight ratio of 7:3 and carrying on ball milling with 100 RPM for 6 hours can obtain the diameter of powder less than 400 nm. As a result, the zirconia slurry can obtain good suspension capacity which is over 48 hours.

Enhancing the Strengths of Adhesion Bonds Between Composite Surface and Coating via UV Treatments

2017 ◽  
Author(s):  
R. Asmatulu ◽  
K. S. Erukala ◽  
M. M. Rahman
Keyword(s):  
Contact Angle ◽  
Uv Radiation ◽  
Uv Light ◽  
Composite Coatings ◽  
Weight Ratio ◽  
High Strength ◽  
Water Contact ◽  
Composite Surface ◽  
Adhesion Properties ◽  
Infrared Spectrometer

Field of composites is rapidly growing in many industries such as aviation, energy and automotive industries. Composites are known to have a high strength to low weight ratio. Significant improvement in the performance of coatings used in the protection of military and civil aircraft has been achieved the last thirty years. Composite coatings are exposed to many environmental conditions, which can significantly affect their properties. In this research, UV light treatment on the surface of composite was introduced to examine its effects on the adhesion properties between the coating and substrate. A cross-cut test was conducted on the composite panels to assess the adhesion of paint to the substrate after the treatments. Coating performance analyses were also carried out using a Fourier transform infrared spectrometer, water contact angle, and optical microscopic images. The first set of panels was treated with UV radiation for 0, 2, 4 and, 8 days, and the surface wettability was also assessed using the contact angle test. Two coats of paints, including a primer and top coat, were used, and the panels were exposed to UV radiation and immersed in water for 500 hrs and 1000 hrs. It was found that untreated panels showed a much higher contact angle of 106°, whereas the contact angle of panels treated with UV radiation was reduced to 47°. The cross-cut tests showed considerable flaking of the coating along the edges and squares of panels that were not treated, and very small flakes along the edges and parts of the grid square on panels that were UV treated, thus confirming the enhancement of coating adhesion between composite and coating surfaces by UV treatments.

scholarly journals Investigation on adsorption capacity of TiO2-P25 nanoparticles in the removal of a mono-azo dye from aqueous solution: A comprehensive isotherm analysis

2014 ◽  
Vol 20 (1) ◽  
pp. 97-107 ◽  
Author(s):  
Mohammad Behnajady ◽  
Shahrzad Yavari ◽  
Nasser Modirshahla
Keyword(s):  
Aqueous Solution ◽  
Crystallite Size ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Correlation Coefficients ◽  
Average Crystallite Size ◽  
Isotherm Models ◽  
Equilibrium Data ◽  
Pseudo Second Order

In this work TiO2-P25 nanoparticles with high surface area have been used as adsorbent for the removal of C.I Acid Red 27 (AR27), as an organic contaminant from aqueous solution. Characteristics of phases and crystallite size of TiO2-P25 nanoparticles were achieved from XRD and the surface area and pore size distribution were obtained from BET and BJH techniques. TiO2-P25 nanoparticles with almost 80% anatase and 20% rutile phases, the average crystallite size of 18 nm, have specific surface area of 56.82 m2 g-1. The effect of various parameters like initial AR27 concentration, pH, contact time and adsorbent dosage has been carried out in order to find desired adsorption conditions. The desired pH for adsorption of AR27 onto TiO2-P25 nanoparticles was 3. The equilibrium data were analyzed with various 2-, 3- and 4-parameter isotherm models. Equilibrium data fitted very well by the 4-parameter Fritz-Schluender model. Results of adsorption kinetics study indicated that the pseudo-second order kinetics provided the best fit with correlation coefficients close to unity.

Preparation and Properties Study on the Composites of Polypropylene and Polyphenylene Sulfide Filled by Modified Molybdenum Disulfide

2009 ◽  
Vol 87-88 ◽  
pp. 345-350
Author(s):  
Jian Qiang Zhang ◽  
Hui Xia Feng ◽  
Jian Hui Qiu
Keyword(s):  
Surface Modification ◽  
Molybdenum Disulfide ◽  
Xrd Analysis ◽  
Sem Analysis ◽  
Polyphenylene Sulfide ◽  
X Ray Diffraction ◽  
Infrared Spectrometer ◽  
Ft Ir ◽  
The Fourier Transform ◽  
Wear Modes

The wet surface modification process were used in this work to get the well lipophilic molybdenum disulfide (MoS2) powders and the modified MoS2 were filled into the polyphenylene sulfide (PPS) and polypropylene (PP) powders with different proportions to make polymeric based composites through hot-press molding equipment. The Fourier transform infrared spectrometer (FT-IR) analysis showed that the modification agents of stearic acid (SA), orγ-Methacryloxypropyl trimethoxy silane(KH570 or A-174), could react with the adsorption hydroxyl(−OH) of the MoS2 powders and finally form chemical coatings, the SA could form a layer of physics wrap too. The powder X-ray diffraction (XRD) analysis reveled that the SA or KH570 could not change the laminated structure of MoS2. The wearability testing showed that the composites filled by modified MoS2 owned the better wearable performances than the filled not one. From minimum to maximum, the wear mass rates of SA/MoS2/PP/PPS, KH570/MoS2/PP/PPS, PP/PPS were 0.7216, 5.4187 and 7.3198 percent in turns. Scanning electronic microscope (SEM) analysis showed the surface modification could uniformize the modified MoS2 to disperse in the polymeric based composites, and also reflect the abrasion mechanism which the particles and the adhering wear modes could all make the mass loss of the testing samples and they coexisted and could transform each other, the former would produce higher loss rates than the later and their leader status would gradually change from the particles wear to the adhering wear during the course of wearing-resisting tests.

scholarly journals Study of the mechanism of nitrophenols sorption on expanded perlite ‒ equilibrium and kinetics modelling

2012 ◽  
Vol 31 (1) ◽  
pp. 101 ◽  
Author(s):  
Zvezdana Yaneva ◽  
Bogdana Koumanova ◽  
Nedyalka Georgieva
Keyword(s):  
Correlation Coefficients ◽  
Isotherm Models ◽  
Expanded Perlite ◽  
Multilayer Adsorption ◽  
Kinetics Modelling ◽  
Equilibrium And Kinetics ◽  
Equilibrium Data ◽  
Intra Particle Diffusion ◽  
Pseudo Second Order ◽  
Basic Characteristics

The adsorption behavior of 2-nitrophenol (2-NP) and 2,4-dinitrophenol (2,4-DNP) on expanded perlite (EP) at equilibrium and kinetic conditions was investigated. The experimental equilibrium data were interpreted by Langmuir, Freundlich, Redlich–Peterson, Temkin and the multilayer isotherm models. Both the Temkin and the multilayer models gave the most satisfactory representation of the experimental data for 2-NP sorption on EP covering the whole concentration range, presuming high initial sorption rate, presence of adsorbent-adsorbate chemical interactions and multilayer adsorption, as the basic characteristics featuring the equilibrium behavior of the system studied. The experimental kinetic results were analyzed by the pseudo-first, pseudo-second order models, Bangham’s model, intra-particle diffusion model, and Elovich kinetic equation. The values of the calculated rate, mass transfer parameters and correlation coefficients proved that chemisorptions/intraparticle diffusion could be outlined as the basic rate controlling mechanisms during 2-NP/2,4-DNP sorption on expanded perlite. Uptake of nitrophenols increased in the order 2-NP < 2,4-DNP.

scholarly journals The Donor – Recipient Weight Ratio is a Reliable Marker for Cell Yield in Hematopoietic Stem Cell Donations

2021 ◽  
Vol 5 (4) ◽  
pp. 1-1
Author(s):  
Wolfgang Rennert ◽  
◽  
Katie Cormier ◽  
Samantha Sprott ◽  
◽  
...  
Keyword(s):  
Bone Marrow ◽  
Regression Analysis ◽  
Stem Cell ◽  
Hematopoietic Stem Cell ◽  
Weight Ratio ◽  
Correlation Coefficients ◽  
Multivariate Regression Analysis ◽  
Cell Yield ◽  
Hematopoietic Stem ◽  
Reliable Marker

Bone marrow transplants remain an import source of hematopoietic stem cells for patients suffering from specific diseases like aplastic anemia, for pediatric patients with malignant and non-malignant blood cell disorders, and for situations in which graft-versus-host disease (GvHD) is a concern. Identifying the optimal donor to achieve a 3-5 x 108/kg of recipient weight TNC yield may be challenging. In an analysis of 687 consecutive donors, donor and procedure characteristics were related to TNC/kg of recipient weight using Spearman correlation coefficients as well as linear and multiple regression analysis. We found correlations between donor WBC (r = 0.17), donor platelet counts (r = 0.15), donor BMI (r = 0.10), and the percentage of donor estimated blood volume accessed for harvesting (r = -0.57) with TNC/kg of recipient weight. The strongest correlation existed between the donor-recipient weight ratio and the TNC/kg (r = 84). In a multivariate regression analysis, the donor-recipient weight ratio influenced the TNC/kg of recipient weight more significantly (adjusted R2 = 0.84) than all other related variables put together. The minimal donor-recipient weight ratio associated with a TNC/kg of at least 3x108/kg of recipient weight was 0.8 (mean 3.425; 95% CI 2.01, 5.8). Using this donor-recipient ratio provides national bone marrow donor registries with a practical and simple measure to assure optimal cell yield outcomes in hematopoietic stem cell donations.

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