scholarly journals Experimental study on phosphate rock modified soil-bentonite as cut-off wall materials

2021 ◽  
Author(s):  
Yuheng Li ◽  
Xing Zeng ◽  
Zhi Lin ◽  
Jia Su ◽  
Tong Gao ◽  
...  
Keyword(s):  
Phosphate Rock ◽  
Adsorption Process ◽  
Exothermic Reaction ◽  
X Ray Diffraction ◽  
Microscopic Mechanism ◽  
Isothermal Adsorption ◽  
Adsorption Performance ◽  
Batch Tests ◽  
Ft Ir ◽  
Modified Soil

Abstract The phosphate rock has great potential value in the application of cut-off walls for heavy metal contaminated sites. The effects of initial concentration of Pb2+, contact time, temperature and pH on the adsorption performance of phosphate rock modified soil-bentonite (PSB) were analyzed by Batch tests, also the microstructure and physicochemical properties of the adsorbent were characterized and analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The results showed that the incorporation of phosphate rock improves the adsorption performance of the mixed material for Pb2+ in acidic environment, and the maximum adsorption amount of PSB can be 154% greater than that of soil-bentonite (SB). The kinetic analysis showed that intraparticle diffusion and liquid film diffusion participate in control of the adsorption process at the same time, and the Langmuir model could fit the isothermal adsorption data better. The adsorption process of PSB to Pb2+ is an exothermic reaction process, and the low temperature environment is beneficial to the adsorption of Pb2+. Studies on the microscopic mechanism show that the PO43− react with Pb2+ in the solution to form phosphate precipitation, and –OH and PO43− on the surface or interlayer of the adsorbent participate in the adsorption process of Pb2+.

Effects of tall fescue biochar on the adsorption behavior of desethyl-atrazine in different types of soil

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 3575-3595
Author(s):  
Wanting Li ◽  
Ruifeng Shan ◽  
Yuna Fan ◽  
Xiaoyin Sun
Keyword(s):  
Tall Fescue ◽  
Adsorption Process ◽  
Exothermic Reaction ◽  
Equilibrium Concentration ◽  
Black Soil ◽  
Adsorption Behavior ◽  
Order Kinetic ◽  
Isothermal Adsorption ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Desethyl-atrazine (DEA) is a metabolite of atrazine that exerts a considerable influence on the environment. In this study, tall fescue biochar was prepared by pyrolysis at 500 °C, and batch experiments were conducted to explore its effect on the adsorption behavior of DEA in red soil, brown soil, and black soil. The addition of biochar increased the equilibrium amount of DEA adsorption for the three soil types. A pseudo-second-order kinetic model most closely fit the DEA adsorption kinetics of the three soils with and without biochar, with a determination coefficient (R2) of 0.962 to 0.999. The isothermal DEA adsorption process of soils with and without biochar was optimally described by the Freundlich and Langmuir isothermal adsorption models with R2 values of 0.98 and above. The DEA adsorption process in the pristine soil involved an exothermic reaction, which became an endothermic reaction after the addition of biochar. Partitioning was dominant throughout the entire DEA adsorption process of the three pristine soils. Conversely, in soils with biochar, surface adsorption represented a greater contribution toward DEA adsorption under conditions of low equilibrium concentration. The overall results revealed that the tall fescue biochar was an effective adsorbent for DEA polluted soil.

scholarly journals Synthesis Fe3O4/Talc nanocomposite by coprecipition-ultrasonication method and advances in hexavalent chromium removal from aqueous solution

2020 ◽  
Vol 38 (9-10) ◽  
pp. 483-501
Author(s):  
Nguyen Thi Huong ◽  
Nguyen Ngoc Son ◽  
Vo Hoang Phuong ◽  
Cong Tien Dung ◽  
Pham Thi Mai Huong ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Adsorption Process ◽  
Low Cost ◽  
Batch Experiments ◽  
X Ray Diffraction ◽  
Order Model ◽  
X Ray ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
Langmuir And Freundlich Equations

The Fe3O4/Talc nanocomposite was synthesized by the coprecipitation-ultrasonication method. The reaction was carried out under a inert gas environment. The nanoparticles were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), fourier-transform infrared spectroscopy (FT-IR) and vibrating sample magnetometry techniques (VSM), the surface area of the nanoparticles was determined to be 77.92 m2/g by Brunauer-Emmett-Teller method (BET). The kinetic data showed that the adsorption process fitted with the pseudo-second order model. Batch experiments were carried out to determine the adsorption kinetics and mechanisms of Cr(VI) by Fe3O4/Talc nanocomposite. The adsorption process was found to be highly pH-dependent, which made the material selectively adsorb these metals from aqueous solution. The isotherms of adsorption were also studied using Langmuir and Freundlich equations in linear forms. It is found that the Langmuir equation showed better linear correlation with the experimental data than the Freundlich. The thermodynamics of Cr(VI) adsorption onto the Fe3O4/Talc nanocomposite indicated that the adsorption was exothermic. The reusability study has proven that Fe3O4/Talc nanocomposite can be employed as a low-cost and easy to separate.

Green Synthesis of Silver Nanoparticles Using a Terrestrial Weed Mucuna bracteata DC and Their Adsorption Study on Reactive Red 120

2020 ◽  
Vol 12 (2) ◽  
pp. 207-214
Author(s):  
N. Mahalaxmi ◽  
E. V. Ramasamy
Keyword(s):  
Dye Removal ◽  
Adsorption Process ◽  
Silver Ions ◽  
Blue Shift ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
Tem Analysis ◽  
Reactive Red 120 ◽  
Pseudo Second Order ◽  
Ft Ir

An eco-friendly method of silver nanoparticle (SNPs) synthesis is presented by utilizing a terrestrial weed, Mucuna bracteata DC. This plant based nanoparticles are effectively reducing anionic dye, Reactive Red 120 by adsorption—an effective method of dye removal from effluents. The method enables the rapid synthesis of SNPs at ambient conditions without any use of hazardous chemicals. The characterization of nanoparticles with UV-visible spectrophotometer indicated the absorption peak at 299 of blue shift; SEM and TEM analysis has revealed the presence of particles with spherical morphology of about 30–80 nm in size; The X-ray diffraction and EDAX studies confirmed the presence of silver atoms; The FT-IR spectra indicated the role of hydroxyl functional groups and amino group of the phyto extract, are responsible for the reduction and stabilizing silver ions in to SNPs. The dye removal results showed that the adsorption process increases when the concentration of nanoparticles increases. The adsorption process obeys Langmuir isotherm (R2 value were 0.994 and RL value lies between 0 and 1) and pseudo second order kinetics (R2 value were 0.998) more effectively. The isotherm and kinetic model confirmed that Mucuna bracteata based SNPs can be used as a suitable adsorbent for the removal of dyes from effluents.

Adsorption Performance of Pummelo Peel to Rhodamine B

2015 ◽  
Vol 723 ◽  
pp. 697-700
Author(s):  
Xiao Dong Li
Keyword(s):  
Waste Water ◽  
Rhodamine B ◽  
Adsorption Process ◽  
Removal Rate ◽  
Physical Adsorption ◽  
Surface Adsorption ◽  
Isothermal Adsorption ◽  
Film Diffusion ◽  
Adsorption Performance ◽  
Adsorption Condition

The adsorption performance of pummelo peel to Rhodamine B (RhB) was tested to study the adsorption regulation and optimal adsorption condition of pummelo peel to dye waste water. The results showed that the RhB removal rate of 0.4 g pummelo peel to 100 mL 140 mg·L-1 RhB reached above 83 % under the condition of 30 °C, pH 8 and 60 min. The theroretical saturation adsorpion amount of pummelo peel was 133 mg·g-1 at 30 °C. The main adsorption pattern of pummelo peel to RhB was physical adsorption adsorption including external liquid film diffusion, surface adsorption and particle internal diffusion. The isothermal adsorption equation and secondary adsorption rate equation of Langmuir could be used to describe the adsorption process of pummelo peel to RhB.

scholarly journals Selective Adsorption of CR (VI) onto Amine-Modified Passion Fruit Peel Biosorbent

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 790
Author(s):  
Xiaolei Zhao ◽  
Junli Zheng ◽  
Shaohong You ◽  
Chongmin Liu ◽  
Linlin Du ◽  
...  
Keyword(s):  
Adsorption Process ◽  
Ph Value ◽  
Selective Adsorption ◽  
Low Cost ◽  
Passion Fruit ◽  
World Health ◽  
Fruit Peel ◽  
Adsorption Performance ◽  
Safe Level ◽  
Ft Ir

This study aimed to prepare surface amino-riched passion fruit peel (DAPFP) by amination reaction with low-cost biomaterials and use it as a biosorbent to adsorb Cr (VI). The specific physicochemical and structural properties of DAPFP were characterized by SEM, EDS, XRD, TG, Zeta, XPS, and FT-IR. The effects of pH value, initial concentration, adsorption time, coexisting ions, and temperature on the adsorption of Cr (VI) were systematically investigated. The results showed that within 90 min, DAPFP could reduce the concentration of Cr (VI) solution (1 mg/L−1) to an allowable safe level of drinking water (0.05 mg/L−1) specified by the World Health Organization. The adsorption process complies with pseudo-second-order kinetics and the Langmuir isotherm model. The adsorption capacity of the prepared biosorbent could reach 675.65 mg/g−1. The results of thermodynamic studies confirmed that the adsorption process was a self-discharging heat process. DAPFP also showed good reusability; even after being used repeatedly five times, it still showed excellent adsorption performance. FT-IR and XPS analyses showed that electrostatic attraction and reduction were the main reasons for the adsorption. By virtue of its low cost and excellent adsorption performance, DAPFP has a potential practical application as an adsorbent in treating Cr (VI) containing wastewater.

scholarly journals Study of Curcumin Adsorption of Nano Fe-based Metal-Organic Framework

2020 ◽  
Vol 4 (4) ◽  
pp. First
Author(s):  
Trang Thị Thu Nguyễn ◽  
Ý Thị Đặng ◽  
Linh Hồ Thùy Nguyễn ◽  
Hạnh Thị Kiều Tạ ◽  
Thắng Bách Phan ◽  
...  
Keyword(s):  
Particle Size ◽  
Metal Organic Framework ◽  
Crystal Formation ◽  
X Ray Diffraction ◽  
Isothermal Adsorption ◽  
Framework Materials ◽  
Metal Organic ◽  
Ft Ir ◽  
Adsorption Desorption ◽  
Organic Framework

Highly porous and biocompatible nano metal-organic framework materials (NMOF) are increasingly being applied in biomedical fields, especially as pharmaceutical adsorbent materials. Curcumin, found in turmeric, is a widely common herb in Eastern which has recently used in many applications in supporting cancer treatment. In the synthesis of MOF materials, the use of surfactants allows to control the morphology, the process of crystal formation and development and particle size of the material. In this research, MIL-100 (Fe) nanomaterials were successfully synthesized at room temperature in the presence of polyvinylpyrrolidone surfactant (PVP) to control the nanoparticle size about 50 nm in size. The synthesized MOF structure and properties were analyzed by using characterization techniques, including powder X-ray diffraction (PXRD), fourier-transform infrared (FT-IR), thermal gravimetric analyses (TGA) and nitrogen isothermal adsorption-desorption at 77 K. The characterization results showed that MIL-100 (Fe) nanomaterials have high crystallinity, large surface area, and highly thermal stability. However, its particle size is very small, only about 50 nm. Curcumin adsorption studies exhibited that this material had the ability to adsorb curcumin with an adsorption capacity up to 64.36 mg g-1. Kinetic and mechanism studies revealed that curcumin adsorption followed the pseudo-second model. In addition, thermodynamic studies proved that this was a spontaneous and exothermic adsorption process.

Adsorption Performance for Ag(І) of an Ethoxycarbonyl Thiourea Chelating Resin

2011 ◽  
Vol 311-313 ◽  
pp. 1077-1080 ◽  
Author(s):  
Shuai Wang ◽  
Jing Jing Xiao ◽  
Hong Zhong ◽  
Gang Zhao ◽  
Yan Long Wen
Keyword(s):  
Adsorption Process ◽  
Langmuir Equation ◽  
Chelating Resin ◽  
Maximum Adsorption Capacity ◽  
Adsorption Enthalpy ◽  
Adsorption Performance ◽  
Adsorption Capacities ◽  
Adsorption Temperature ◽  
Endothermic Process ◽  
Ft Ir

Effects of initial concentration of Ag(І), concentration of HNO3, contact time and adsorption temperature on adsorption capacities of a novel polystyrene modified ethoxycarbonyl thiourea resin were investigated, and the maximum adsorption capacity of Ag(І) reached 4.11 mmol·g-1. The adsorption kinetics was well fitted Boyd’s diffusion equation of liq·uid film, so the adsorption was controlled by liquid film diffusion. The experimental date fitted Langmuir equation, and the correlation coefficient was close to 1. The positive value of adsorption enthalpy ΔH is indicative of an endothermic process. FT-IR characteristic peaks of ethoxycarbonyl and thiourea groups changed obviously fore-and-aft adsorption, which means that the corresponding functional groups coordinate with Ag during the adsorption process.

Preparation and characterization of a new sawdust/MNP/PEI nanocomposite and its applications for removing Pb (II) ions from aqueous solution

2018 ◽  
Vol 78 (12) ◽  
pp. 2469-2480
Author(s):  
Avat Ghasemi ◽  
Mahmoud Reza Sohrabi ◽  
Fereshteh Motiee
Keyword(s):  
Aqueous Solution ◽  
Contact Time ◽  
Adsorption Process ◽  
Aqueous Media ◽  
X Ray Diffraction ◽  
Phase Contact Time ◽  
X Ray ◽  
Langmuir Adsorption ◽  
Ft Ir

Abstract A new sawdust/magnetite nanoparticles/polyethyleneimine (SD/MNP/PEI) nanocomposite was synthesized by grafting polyethyleneimine (PEI) to magnetic sawdust. Features of SD/MNP/PEI were characterized using Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and scanning electron microscopy (SEM). SD/MNP/PEI was used as an adsorbent for the removal of lead (Pb (II)) from aqueous solution. The effects of independent variables including pH of solution, adsorbent dose and contact time were performed and adsorption isotherms were obtained. Experimental results show that priority effective variables were pH and the amount of nanocomposite, and it was found that the sorption capacity increases with the increasing phase contact time. The adsorption process followed the Langmuir adsorption isotherm. Although SD and SD/MNP do not show a high affinity for the adsorption of Pb (II) in aqueous media, polyethyleneimine cross-linked on SD/MNP showed 40 and 66% increases, respectively, in the adsorption of Pb (II) compared to the SD and SD/MNP. It was found that SD/MNP/PEI removes more efficiently lead ions from aqueous solutions than the SD, SD/MNP. Desorption of the lead from the SD/MNP/PEI was conducted. It was proved that SD/MNP/PEI has excellent properties and can be used as a sorbent of multi-use.

scholarly journals Adsorption of REEs from Aqueous Solution by EDTA-Chitosan Modified with Zeolite Imidazole Framework (ZIF-8)

2021 ◽  
Vol 22 (7) ◽  
pp. 3447
Author(s):  
Sihan Feng ◽  
Xiaoyu Du ◽  
Munkhpurev Bat-Amgalan ◽  
Haixin Zhang ◽  
Naoto Miyamoto ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Adsorption Capacity ◽  
Adsorption Process ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
Growth Method ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
Multiple Cycles ◽  
Adsorption Desorption

Chitosan (CS) modified with ethylenediamine tetraacetic acid (EDTA) was further modified with the zeolite imidazole framework (ZIF-8) by in situ growth method and was employed as adsorbent for the removal of rare-earth elements (REEs). The material (EDTA–CS@ZIF-8) and ZIF-8 and CS were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), and nitrogen adsorption/desorption experiments (N2- Brunauer–Emmet–Teller (BET)). The effects of adsorbent dosage, temperature, the pH of the aqueous solution, contact time on the adsorption of REEs (La(III), Eu(III), and Yb(III)) by EDTA–CS@ZIF-8 were studied. Typical adsorption isotherms (Langmuir, Freundlich, and Dubinin–Radushkevich (D-R)) were determined for the adsorption process, and the maximal adsorption capacity was estimated as 256.4 mg g−1 for La(III), 270.3 mg g−1 for Eu(III), and 294.1 mg g−1 for Yb(III). The adsorption kinetics results were consistent with the pseudo-second-order equation, indicating that the adsorption process was mainly chemical adsorption. The influence of competing ions on REE adsorption was also investigated. After multiple cycles of adsorption/desorption behavior, EDTA–CS@ZIF-8 still maintained high adsorption capacity for REEs. As a result, EDTA–CS@ZIF-8 possessed good adsorption properties such as stability and reusability, which have potential application in wastewater treatment.

scholarly journals Removal and Comparative Adsorption of Anionic Dye on Various MgAl synthetic Clay

2021 ◽  
Vol 11 (6) ◽  
pp. 14986-14997
Keyword(s):  
Congo Red ◽  
Adsorption Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Order ◽  
Batch System ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
Red Dye ◽  
Synthetic Clay

In this study, the adsorption of Congo red dye in an aqueous solution on two synthetic clay adsorbents, MgAl-LDH (2:1) and MgAl-LDH (3:1), was investigated using batch system experiments. The adsorbents' characterization was carried out by various techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy FT-IR. The conditions applied in the adsorption experiments including the mass of adsorbent, initial concentration, contact time, pH, and temperature. The kinetic data were modeled by pseudo-first-order and pseudo-second-order. Langmuir and Freundlich's models analyzed the adsorption isotherms of Congo red on the two adsorbents. It was found that the adsorption process could be described by Langmuir isotherm. The maximum amount of adsorption is 285.71 and 166.66 mg/g for MgAl-LDH (2:1) and MgAl-LDH (3:1), respectively. Thermodynamic parameters such as enthalpy ∆H°, enthalpy ∆S°, and free enthalpy ∆G° were also evaluated to predict the nature of adsorption.

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