scholarly journals Lignocellulose-Based Superabsorbent Polymer Gel Crosslinked with Magnesium Aluminum Silicate for Highly Removal of Zn (II) from Aqueous Solution

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4161
Author(s):  
Yuhong An ◽  
Wanqi Zhang ◽  
Hui Liu ◽  
Yuan Zhong ◽  
Zichu Hu ◽  
...  

Lignocellulose (LCE) was ultrasonically treated and intercalated into magnesium aluminum silicate (MOT) clay to prepare a nano-lignocellulose magnesium aluminum silicate polymer gel (nano-LCE-MOT) for the removal of Zn (II) from aqueous solution. The product was characterised using nitrogen adsorption/desorption isotherm measurements, Fourier-transform infrared spectroscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy. The conditions for the adsorption of Zn (II) on nano-LCE-MOT were screened, and adsorption kinetics and isotherm model analysis were carried out to explore the adsorption mechanism and achieve the optimal adsorption of Zn (II). Optimal adsorption was achieved at an initial Zn (II) concentration of 800 mg/L at 60 °C in 160 min at a pH of 4.52. The adsorption kinetics were explored using a pseudo-second-order model, with the isotherm adsorption equilibrium found to conform to the Langmuir model. The maximum adsorption capacity of the nano-LCE-MOT polymer gel toward Zn (II) is 513.48 mg/g. The materials with adsorbed Zn (II) were desorbed using different media, with HCl found to be the most ideal medium to desorb Zn (II). The optimal desorption of Zn (II) was achieved in 0.08 mol/L HCl solution at 65 °C in 60 min. Under these conditions, Zn (II) was almost completely desorbed from the adsorbents, with the adsorption effect after cycling being slightly different from that of the initial adsorption.

2018 ◽  
Vol 5 (1) ◽  
pp. 171662 ◽  
Author(s):  
Bin Feng ◽  
Wenzhong Shen ◽  
Liyi Shi ◽  
Shijie Qu

Owing to the unique microporous structure and high specific surface area, porous carbon could act as a good carrier for functional materials. In this paper, polyacrylonitrile (PAN)-based porous carbon materials (PPC-0.6-600, PPC-0.8-600, PPC-0.6-800 and PPC-0.8-800) were prepared by heating KOH at 600°C and 800 o C for the removal of Cr(VI) from aqueous solution. The adsorbent was characterized by the techniques of Fourier transform infrared spectroscopy (FT-IR), elementary analysis, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and N 2 adsorption techniques. The results showed that the adsorption capacity increased with decreasing pH value of the initial solution. The adsorption capacity of Cr(VI) on PPC-0.8-800 was much greater than that on other materials, and maximum adsorption capacity were calculated to be 374.90 mg g −1 . Moreover, PPC-0.8-800 had superior recyclability for the removal of Cr(VI) from wastewater, about 82% of its initial adsorption capacity was retained even after five cycles. The result of kinetic simulation showed that the adsorption of Cr(VI) on the PAN-based porous carbon could be described by pseudo-second-order kinetics. The adsorption process was the ionic interaction between protonated amine groups of PPC and HCrO 4 - ions.


2020 ◽  
Vol 993 ◽  
pp. 1426-1431
Author(s):  
Bei Gang Li ◽  
Hai Yang Yin

A novel calcium alginate (SA/Ca) gel pellet adsorbent was prepared by ion exchange reaction and polymerization between sodium alginate (SA) and Ca2+ in the solution, and characterized by SEM, EDS, FTIR and XRD. Taking acid orange II ( AO II) dye as the adsorption object, the influence of some important conditions about preparation and adsorption on SA/Ca properties was discussed in detail. The adsorption kinetics were studied. The results show that SA/Ca adsorbent has good adsorption effect on AO II dye under the conditions of the mass concentration ratio 2 : 5 of SA and CaCl2 solutions and reaction time of 2h at 25°C. When the adsorbent dosage is 4g/L and initial dye concentration of natural pH is 1000 mg/L, the adsorption equilibrium can basically reach in 180 min at 25°C with the adsorption capacity of 225mg/g and more than 90% of removal efficiency. The adsorption kinetics fully fit pseudo-second order model. The characterization results indicate that the SA powder is composed of various irregular particles, while dry SA/Ca solid are all pellets with diameter of about 1mm. The surface of inhomogeneous spheres is stacked with obstacles, and folds and ravines coexist. Ca2+ and most Na+ in SA molecule carried out ion exchange and formed a stable network-structure polymer SA/Ca gel pellets, which can effectively remove acid dyes from wastewater, and are easy to be separated after adsorption. As a biopolymer adsorbent with simple preparation method, environmental friendliness and non-toxic side effects, SA/Ca has good development potential and application prospects.


RSC Advances ◽  
2017 ◽  
Vol 7 (28) ◽  
pp. 17095-17106 ◽  
Author(s):  
Nan Sun ◽  
Wenxin Shi ◽  
Lixin Ma ◽  
Shuili Yu

Attapulgite (ATP) is a type of natural magnesium aluminum silicate mineral and has been applied as an adsorbent to remove organic pollutants and heavy metals in aqueous solution.


2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Nur Izzah Iwanina Zamri ◽  
Siti Lailatul N. Zulmajdi ◽  
Nur Zafirah A. Daud ◽  
Abdul Hanif Mahadi ◽  
Eny Kusrini ◽  
...  

Abstract In the present study, pectin-alginate-titania (PAT) composites were synthesized and the adsorptive removal behavior of methylene blue (MB) from aqueous solution, as a model of synthetic organic effluents, onto the prepared PAT composites were investigated by monitoring the effect of contact time, initial MB concentration, and temperature. The adsorption isotherm data were fitted well with the Freundlich isotherm model, suggesting the surface heterogeneity of the PAT composites and that the MB adsorption occurred on the active sites on multilayer surface of the composites. The adsorption kinetics of MB was demonstrated to be pseudo-second order, governed by two intraparticle diffusion rates, and the adsorption process was exothermic, spontaneous, and more disorder. The Langmuir isotherm model suggested that the maximum adsorption capacity of MB on the PAT composites was in the range of 435–637 mg g–1. In general, it increased with the TiO2 NPs content in the PAT composites, due most likely to the increase in surface area exposing more functional groups of the pectin and alginate to interact with the synthetic dye. The adsorptive removal of MB by the PAT composites was found to be more efficient compared with many other reported adsorbents, such as graphene oxide hybrids, pectin microspheres, magnetite-silica-pectin composites, clay-based materials, chemically treated minerals, and agricultural waste. The present study therefore demonstrated for the first time that PAT composites are not only promising to be utilized as an adsorbent in wastewater treatment, but also provide an insight into the adsorption mechanism of the synthetic dyes onto the biopolymers-titania composites. Graphic abstract Insight into the adsorption kinetics, mechanism, and thermodynamics of methylene blue from aqueous solution onto pectin-alginate-titania composite microparticles.


2016 ◽  
Vol 73 (11) ◽  
pp. 2761-2771 ◽  
Author(s):  
Hongliang Chen ◽  
Juan Zheng ◽  
Zhongqiong Zhang ◽  
Qian Long ◽  
Qiuyun Zhang

Physicochemical characteristics and Mn2+ adsorption of annealed red mud were investigated in this study. The annealing temperature (105–900 °C) changed the mineralogical components and the point of zero charge of red mud. By comparison, annealed red mud at 700 °C (ARM700) had a better adsorption effect than other annealed samples, associated with the activated components of available Fe2O3, Al2O3, SiO2 and Na5Al3(SiO4)3CO3 (natrodavyne). The removal efficiency of Mn2+ by ARM700 was dependent on initial pH, contact time, and initial Mn2+ concentration of aqueous solution and was ∼56.5% with initial Mn2+ concentration 385 mg/L at initial pH > 5. The kinetics process was predicted better by the pseudo-second-order model. The Langmuir isotherm displayed a better fitting model than the Freundlich isotherm and the Mn2+ maximum adsorption capacity of ARM700 was 88.3 mg/g. The competing effects of Cu2+ and Zn2+ on Mn2+ removal were most obvious. There was efficient Mn2+ removal at the application of ARM700 to the leachate of electrolytic manganese residue.


2021 ◽  
Author(s):  
Sabarish Radoor ◽  
Jasila Karayil ◽  
Aswathy Jayakumar ◽  
Jyotishkumar Parameswaranpillai ◽  
Suchart Siengchin

Abstract In the present work, we modified ZSM-5 zeolite using a bio polymer poly (diallyl dimethyl ammonium chloride) and employed it for the removal of cationic dye, methylene blue from aqueous solution. The chemical and physical properties of the modified ZSM-5 zeolite were investigated using XRD, FTIR, SEM, TEM, nitrogen adsorption, TGA and 27Al NMR. Modified ZSM-5 zeolite possesses high surface area and pore diameter which was confirmed from SEM, TEM and nitrogen adsorption analysis. Adsorption of methylene blue on zeolite was investigated by batch adsorption technique. The effect of different parameters such as zeolite dosage, initial methylene blue concentration, temperature, pH and contact time on the adsorption process was discussed. Maximum adsorption capacity (4.31 mg/g) was achieved using 0.1g of modified ZSM-5 zeolite at the optimum conditions (initial dye concentration: 10 mg/L, pH: 10, temperature:30oC and contact time: 300 min). The experimental data were fitted into Langmuir and Freundlich models and the results indicate that the adsorption process followed Freundlich isotherm. Kinetic data were investigated using pseudo-first-order and pseudo-second-order models. Kinetic analysis indicates that pseudo-second-order model is more suitable to describe adsorption of MB on modified ZSM-5 zeolite. The reusability test suggests that the adsorbent could be reused at least six times without significant loss in removal efficiency.


2019 ◽  
Vol 128 (1B) ◽  
pp. 5
Author(s):  
Nguyễn ĐỨC Vũ Quyên ◽  
Trần Ngọc Tuyền ◽  
Đinh Quang Khiếu ◽  
Đặng Xuân Tín ◽  
Bùi Thị Hoàng Diễm ◽  
...  

Carbon nanotubes (CNTs) synthesized by chemical vapour deposition without using hydrogen were oxidized with 0.1 M potassium permanganate at 40<sup>o</sup>C for 2 hours and exhibited high Cu<sup>II</sup> adsorption capacity from aqueous solution. X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), scanning electron microscope (SEM), transmission electron microscope (TEM) and nitrogen adsorption/desorption isotherms were used to characterize the oxidized CNTs. After oxidizing, the obtained CNTs were used to remove Cu<sup>II</sup> from aqueous solution. With Cu<sup>II</sup> initial concentration of 20 mg.L<sup>-1</sup>, at pH of 4 and adsorbent dosage of 0.2 g.L<sup>-1</sup>, the oxidized CNTs exhibited high Cu<sup>II</sup> adsorption ability with maximum adsorption capacity of 174.4 mg.g<sup>-1</sup>.


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