scholarly journals Adsorption of U(VI) onto Amidoxime-functionalized Hydrothermal Carbon in the Presence of Ca-U(VI)-CO3 Complexes

2020 ◽  
Vol 1 (2) ◽  
Author(s):  
Yinghui XIE ◽  
Zhimmin DONG ◽  
Haoyan ZHANG ◽  
Runze ZHOU ◽  
Yunhai LIU ◽  
...  
Keyword(s):  
Ph Value ◽  
Spherical Surface ◽  
Great Influence ◽  
Amino Nitrogen ◽  
Single Layer ◽  
Adsorption Model ◽  
Potential Measurement ◽  
Uranium Adsorption ◽  
Isotherm Adsorption ◽  
Adsorption Desorption

The aim is collecting uranium from groundwater in which uranium mainly exists in negative species, the amidoxime-functionalized hydrothermal carbon (AO-HTC) was synthesized. From the results of N2 adsorption-desorption and SEM, AO-HTC is a small spherical surface; FT-IR and Elemental analysis showed that the amidoxime group was successfully grafted onto the surface of the material; Zeta-potential measurement showed that the amino nitrogen atom is protonated in the oxime group. The optimum pH value of AO-HTC for uranium adsorption is 6.0, and the adsorption equilibrium is reached within 80 min, which is in accordance with the pseudo-second order adsorption kinetic model. The adsorption of uranium by AO-HTC accords with the Langmuir isotherm adsorption model, and the single-layer saturated adsorption capacity is 254.13mg·g-1. The thermodynamic parameters calculated by the adsorption isotherm indicate that AO-HTC adsorption of uranium is a spontaneous endothermic chemical process and Carbonate ion, calcium ion and humic acid concentration have great influence on uranium adsorption. The experiments results show that AO-HTC has the potential to elimination of U(VI) from groundwater.

scholarly journals Kinetics of Cr(VI) adsorption from aqueous medium onto bentonite

2020 ◽  
Vol 11 (15) ◽  
Author(s):  
Rada Petrović
Keyword(s):  
Heavy Metals ◽  
Aqueous Medium ◽  
Ph Value ◽  
Second Order ◽  
Human Beings ◽  
Adsorption Model ◽  
Solution Ph ◽  
Initial Ph ◽  
Isotherm Adsorption ◽  
Pseudo Second Order

Because of its abundance and toxicity, heavy metals have become a seriousenvironmental problem. The presence of heavy metals, such as Cr(VI), in thewatercourses leads to numerous health problems in humans and animals. Cr(VI) ishighly toxic, even in low concentrations. Because of its carcinogenic, mutagenic andteratogenic effects on human beings, Cr(VI) is considered one of the most criticalpollutants. Due to this, it is necessary to remove Cr(VI) from wastewater prior to itsdischarge into the recipient.This paper studied the possibility for application of bentonite as an adsorbent forCr(VI) from aqueous medium. The characterization of bentonite was determined withchemical composition, specific surface, XRD method and FTIR. Optimal parameterssuch as pH of solution, adsorbent weight, time of adsorption and temperaturewere examined. Values of those parameters were: initial pH value of solution pH=2,adsorbent weight 2 g, time of adsorption 60 min, temperature 308 K. Experimentaldata were obtained by Freundlich and Langmuir isotherm adsorption models as wellas pseudo-first and pseudo-second order kinetics. Results were best described withFreundlich isotherm adsorption model and pseudo-second order kinetics.

scholarly journals Analysis of the Application Potential of Coffee Oil as an Ilmenite Flotation Collector

Minerals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 505 ◽  
Author(s):  
Wang ◽  
Xiao ◽  
Ma ◽  
Li ◽  
Chen ◽  
...  
Keyword(s):  
Zeta Potential ◽  
Ph Value ◽  
Foam Stability ◽  
Great Influence ◽  
Potential Measurement ◽  
Ilmenite Concentrate ◽  
Foam Properties ◽  
Application Potential ◽  
Coffee Oil ◽  
Flotation Collector

Coffee grounds are the most significant production waste in the coffee industry and contain about 15% coffee oil. Coffee oil is rich in fatty acids and polyphenols, which have great application potential in the flotation of oxidized minerals. In this study, coffee oil as a green flotation collector for ilmenite was investigated by micro-flotation, zeta potential measurement, and foam stability analysis. The results of zeta potential reveal that both coffee oil and MOH can be adsorbed on the ilmenite surface at pH 6.7, and the chemical adsorption mode is dominant. However, when the pH is 2.8, the adsorption capacity of coffee oil on the ilmenite surface is much larger than that of MOH. The pH value of the pulp has little effect on the foam properties in the coffee oil solution and has a great influence on the foaming performance and foam stability of the MOH solution. When coffee oil is used as a collector, the grade of TiO2 in ilmenite concentrate is increased from 21.68% to 46.83%, and the recovery is 90.22%, indicating that the potential of coffee oil in the application of ilmenite flotation is large.

scholarly journals Study on synthesis of MoS2 modified g-C3N4 materials for treatment of Direct black 38 dye

2018 ◽  
Vol 9 (3) ◽  
pp. 169-176
Author(s):  
Thi Lan Phung ◽  
Thi Kim Giang Nguyen
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Photocatalytic Performance ◽  
Ph Value ◽  
Light Irradiation ◽  
Order Kinetic ◽  
Two Factors ◽  
Pseudo Second Order ◽  
Enhanced Adsorption ◽  
Adsorption Desorption

Pure g-C3N4 and MoS2 modified g-C3N4 materials were synthesized using a facile heating method and a low-temperature hydrothermal method, respectively. The obtained samples were characterized by XRD pattern and N2 adsorption-desorption technique at 77K. The adsorption and photocatalytic performance of all obtained samples were investigated by discoloration of direct black 38 dye in the dark and under visible light irradiation. The results showed that all obtained samples exhibited good discoloration efficiency of direct black 38 dye. The two factors including pH values and Mo loading effected mainly on elimination efficiency of direct black 38 dye. MoS2 modified g-C3N4 materials possessed the more enhanced adsorption and photocatalytic performance in comparison to pure g-C3N4 at pH value of 3.5, with adsorbent dosage of 0.1 g/L. Furthermore, it was found that the adsorption process and photo-catalysis simultaneously occurred under visible light irradiation and followed up a pseudo-second-order kinetic reaction of Langmuir - Hinshelwood model. g-C3N4 và g-C3N4 biến tính bởi MoS2 đã được tổng hợp theo phương pháp nung đơn giản và phương pháp thủy nhiệt ở nhiệt độ thấp tương ứng. Các mẫu tổng hợp đã được đánh giá đặc trưng bởi các phương pháp hiện đại như giản đồ nhiễu xạ tia X, phương pháp hấp phụ-khử hấp phụ N2 ở 77K. Khả năng hấp phụ và quang hóa xúc tác của các vật liệu tổng hợp đã được nghiên cứu bởi quá trình phân hủy màu thuốc nhuộm direct black 38 trong điều kiện bóng tối và chiếu sáng bởi ảnh sáng nhìn thấy của đèn chiếu sáng sợi đốt wolfram (220V-100W). Các kết quả nghiên cứu chỉ ra rằng các mẫu tổng hợp đều có hiệu suất xử lý màu cao đối với thuốc nhuộm direct black 38. Hai yếu tố gồm pH dung dịch và hàm lượng MoS2 ảnh hưởng chính đến hiệu suất xử lý màu direct black 38. g-C3N4 biến tính bởi MoS2 luôn thể hiện hiệu suất hấp phụ và quang hóa cao hơn so với g-C3N4 tinh khiết. Hơn nữa, khi được chiếu sáng bởi ánh sáng nhìn thấy thì quá trình hấp phụ và quá trình quang hóa thuốc nhuộm direct black 38 trên các vật liệu tổng hợp đã xảy ra đồng thời và mô hình Langmuir - Hinshelwood động học bậc 2 đã được đề xuất cho quá trình này.

Effect of the Thick-Walled Steel Tubular Joint Stiffness on the Overall Stability of a Single-Layer Latticed Shell

2014 ◽  
Vol 501-504 ◽  
pp. 791-795
Author(s):  
Lan Chen ◽  
Bo Yin
Keyword(s):  
Great Influence ◽  
Joint Stiffness ◽  
Single Layer ◽  
Steel Tube ◽  
Tube Section ◽  
Overall Stability ◽  
Rectangular Tube ◽  
New Type ◽  
Tubular Joint ◽  
Geometric Nonlinear Analysis

As a new type of joint, the thick-walled steel tubular joint is applied in the single-layer latticed shell to solve the connectivity problem of rectangular tube. In combination with the design of practical project, the effect of the new joint stiffness on the overall stability of a single-layer latticed shell and the value of joint stiffness are studied by ANSYS. Some parameters as the rectangular tube section, the thickness of thick-walled steel tube and connecting plate are taken into account in the process of geometric nonlinear analysis. The results show that joint stiffness has great influence on the overall stability of a single-layer latticed shell and the range of effect gradually increases with the growth of rectangular tube section.

scholarly journals Optimization of process parameters and kinetics of adsorption treatment of thallium-containing wastewater

2019 ◽  
Vol 118 ◽  
pp. 01025
Author(s):  
Tao Wen ◽  
Yuanyuan Zhao ◽  
Youze Xu ◽  
Jing Guo ◽  
Guangyi Fu ◽  
...  
Keyword(s):  
Ph Value ◽  
Removal Rate ◽  
Toxic Metal ◽  
Chemical Precipitation ◽  
Chelating Resin ◽  
Adsorption Model ◽  
Kinetics Of Adsorption ◽  
Optimization Of Process Parameters ◽  
Adsorption Treatment ◽  
Adsorption Rates

Thallium is an extremely toxic metal and abundant in industrial wastewater but little studied. In order to understand the optimal adsorption kinetic parameters of the chelating resin containing hydrazine wastewater, we carried out adsorption experiments on the cerium-containing wastewater treated by chemical precipitation. In this chapter, the optimum adsorption conditions, adsorption model, dynamic adsorption curve and desorption and regeneration of adsorbent were determined at different pH, temperature, adsorption time and different adsorbent dosage. The results show that the removal rate of thallium wastewater by resin is up to 97.5% when the pH value is 9. The optimum adsorption temperature is 30 and the adsorption reached equilibrium at 80 min. The adsorption process is consistent with Lagergren quasi-second-order adsorption and Langmuir isotherm model. The regenerative properties of the resin show that the resin adsorption rates still reach 95.8% after repeat use for six times. In summary, the chelating resin has good adsorption and reusability to the thallium-containing wastewater

Preparation of Cr Metal Supported on Sulfated Zirconia Catalyst

2019 ◽  
Vol 948 ◽  
pp. 221-227
Author(s):  
Latifah Hauli ◽  
Karna Wijaya ◽  
Ria Armunanto
Keyword(s):  
Sulfated Zirconia ◽  
Reduction Process ◽  
Catalyst Preparation ◽  
Impregnation Method ◽  
Wet Impregnation ◽  
Zirconia Catalyst ◽  
Isotherm Adsorption ◽  
Sulfated Zirconia Catalyst ◽  
Adsorption Desorption ◽  
Wet Impregnation Method

Catalyst of Chromium (Cr) metal supported on sulfated zirconia (SZ) was prepared by wet impregnation method. This study aim to determine the optimal concentration of Cr metal that impregnated on SZ catalyst. Preparation of catalyst was conducted at different concentrations of Cr metal (0.5%, 1%, 1.5% (w/w)), impregnated on SZ catalyst, then followed by the calcinationand reduction process. Catalysts were charaterized by FTIR, XRD, XRF, SAA, TEM, and acidity test. The results showed the Cr/SZ 1% had the highest acidity value of 8.22 mmol/g which confirmed from FTIR spectra. All the crystal phase of these catalysts were in monoclinic. The specific surface area increased with the increasing of Cr metal concentration on SZ catalyst and the isotherm adsorption-desorption of N2 gas observed all the catalysts as mesoporous material. The impregnation process formed particles agglomeration.

Mechanical Strength of Sago/Urea Formaldehyde Particleboard Affected by the Particle Size

2016 ◽  
Vol 833 ◽  
pp. 3-10
Author(s):  
Tay Chen Chiang ◽  
Sinin Hamdan ◽  
Mohd Shahril Osman
Keyword(s):  
Mechanical Properties ◽  
Manufacturing Industry ◽  
Urea Formaldehyde ◽  
Great Influence ◽  
Single Layer ◽  
Milling Process ◽  
Raw Material ◽  
Huge Amount ◽  
Testing Method ◽  
Sago Waste

Every year, the sago processing industry in Sarawak-Mukah had generated huge amount of sago waste after the milling process and scientists have employ the waste into composite material. The fabrication and testing method are based on the Japanese A5908 Industrial Standard. Single-layer particleboards with targeted density of 600kg/m3 were produced from different sizes of sago particles. The mechanical properties of sago waste were investigated to study the feasibility of using this sample as a raw material in particleboard manufacturing. The results of the test demonstrate that samples with different sizes of particles have great influence on the mechanical properties such as Young’s Modulus, Tensile Strength and Impact Strength. The findings show that the performance of the board is affected by the different sizes of sago particles used in the experiment and had proved that sago plants can be used as an alternative raw material in the particleboard manufacturing industry.

Electromagnetic Performance due to Tooth-tip Design in Fractional-slot PM Brushless Machines

2015 ◽  
Vol 6 (4) ◽  
pp. 860
Author(s):  
Mohd Luqman Mohd Jamil ◽  
Zulfikri Zaki Zolkapli ◽  
Auzani Jidin ◽  
Raja Nor Firdaus Raja Othman ◽  
Tole Sutikno
Keyword(s):  
Double Layer ◽  
Great Influence ◽  
Single Layer ◽  
Torque Ripple ◽  
Element Analysis ◽  
Cogging Torque ◽  
Torque Density ◽  
Iron Modification ◽  
Winding Machine ◽  
Electromagnetic Performance

Permanent Magnet (PM) machines are favorable as an alternative to other machine topologies due to simpler construction and high torque density. However, it may result hight torque ripple due to an influence of cogging torque and electronic commutation. In this paper, comparisons of phase back-emf, static torque and cogging torque due to influence of tooth-tip asymmetry in 12-slot/10-pole double-layer and 12-slot/10-pole single layer winding machines are carried out using 2D Finite-Element Analysis. At rated condition, the stator asymmetry has great influence on the torque performance as there is significant reduction of torque ripple in 12-slot/10-pole mahine equipped with single layer winding than one equipped with double layer winding machine. It si confirmed that an optimum torque performance is desirable via stator iron modification in PM machines.

The Effect Of Weight Fraction And Size On The Properties Of Sago Particles Urea Formaldehyde Particleboard

2015 ◽  
Vol 73 (1) ◽  
Author(s):  
Tay Chen Chiang ◽  
Sinin Hamdan ◽  
Mohd Shahril Osman
Keyword(s):  
Urea Formaldehyde ◽  
Great Influence ◽  
Single Layer ◽  
Weight Fraction ◽  
Solid Content ◽  
Wood Products ◽  
Density Level ◽  
Testing Method ◽  
Uf Resin ◽  
Low Emission

We live in a world where wood products are hard to ignore. The sheer flexibility in the number of applications where the wood is used means that it is one of the most sought resources in the world. The wood products industry faces challenges in promoting sustainable management of forest resources. Composite materials have advantage of having an optimized performance, minimized weight and volume, cost effectiveness, chemical resistance and resistance to biodegradation. The research in this paper is focused on sago particles with adhesive of low emission urea formaldehyde (UF) resin 51.6% solid content. The fabrication and testing method are based on JIS A 5908 standard. A single-layer particleboard by using the sago particles has been established at targeted density level 600kg/m3. Particles with weight fractions of 90%, 85%, 80%, 75% and 70% were used in the fabrication of sago composite boards. The results of the test demonstrated that the samples with different weight fraction and size have great influence on the mechanical properties like: MOR, screw test and internal bonding. The findings had demonstrated that the level of weight fraction and size had affects the performance of a board. At the next stage of the research the comparison between sago and wood particleboard will be carried out to identify the feasibility of these materials in the industrial application.

scholarly journals Effect of Sodium Periodate on the Adsorption Capacity of Silica-Lignin from Rice Husk on Chromium(VI)

2019 ◽  
Vol 22 (6) ◽  
pp. 242-249 ◽  
Author(s):  
Yati B. Yuliyati ◽  
Solihudin Solihudin ◽  
Atiek Rostika Noviyanti
Keyword(s):  
Adsorption Capacity ◽  
Surface Area ◽  
Sodium Periodate ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Adsorption Model ◽  
Chromium Vi ◽  
Reactive Groups ◽  
Isotherm Adsorption

Reactive groups such as silanol, hydroxyl, and carbonyl groups in silica-lignin composites play a role in binding to chromium(VI) ions. The activation of functional groups in silica-lignin can be increased by the addition of an activator such as sodium periodate, which can also oxidize the lignin monomer (guaiasil) to ortho-quinone. This study aimed to obtain silica-lignin composites from rice husks activated by sodium periodate with a high surface area. Composite absorption was tested on chromium(VI) adsorption. Silica-lignin isolation was carried out by using the sol-gel method at concentrations of sodium hydroxide 5, 10, 15, and 20% (b/b). Silica-lignin activated with sodium periodate 10% (b/b) had the smallest particle size of about 8μm, with a surface area of 14.0888 m2.g-1 and followed Halsey isotherm adsorption model, with an adsorption capacity of 0.3054 mg.g-1.

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