scholarly journals Chemically/Electrically-assisted Regeneration of Polyacrylonitrile-based Hydrogel Adsorbed Heavy Metals 

2021 ◽  
Author(s):  
Amany A. El Mansoub ◽  
Marwa El-Sayed ◽  
Rasha M. El Nashar ◽  
Hussein M. Fahmy ◽  
Abdelghani M.G. Abulnour
Keyword(s):  
Heavy Metals ◽  
Kinetic Data ◽  
Industrial Effluents ◽  
Electrically Assisted ◽  
Adsorption Capacities ◽  
Efficient Regeneration ◽  
Removal Of Heavy Metals ◽  
Pseudo Second Order ◽  
Chemical Regeneration ◽  
Regeneration Efficiency

Abstract Adsorption is an important technology for the removal of heavy metals from industrial effluents. Efficient regeneration of exhausted adsorbents is essential for improving the applicability of different adsorbents. In this work an adsorptive polyacrylonitrile-based hydrogel was characterized and investigated in terms of adsorption/regeneration using both conventional chemical and electrical-assisted regeneration techniques. The hydrogel characterization includes FTIR, XRD, SEM, EDAX, porosity, and electrical conductivity. Hydrogel performance in adsorption and conventional chemical regeneration was tested. Further, electrically-assisted regeneration using a specially designed cell was also investigated.The maximum adsorption capacities for chromium and nickel were 8.082, and 17.437 mg/g, respectively. The isotherm data fitted Freundlich, while kinetic data fitted pseudo-second-order model.Conventional chemical desorption showed regeneration efficiency of 15.58, and 27.27 % for chromium and nickel, respectively. While, the electrically-assisted regeneration showed much higher values of 51.6, and 98.3 % for chromium and nickel, respectively indicating the merit of using electrically-assisted chemical regeneration for enhancing heavy metals adsorbing hydrogel applicability.

scholarly journals Sawdust for the Removal of Heavy Metals from Water: A Review

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4318
Author(s):  
Elie Meez ◽  
Abbas Rahdar ◽  
George Z. Kyzas
Keyword(s):  
Heavy Metals ◽  
Adsorption Mechanism ◽  
Freundlich Isotherm ◽  
Order Kinetic ◽  
Suitable Material ◽  
Removal Of Heavy Metals ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
And Control ◽  
Environmental Agencies

The threat of the accumulation of heavy metals in wastewater is increasing, due to their abilities to inflict damage to human health, especially in the past decade. The world’s environmental agencies are trying to issue several regulations that allow the management and control of random disposals of heavy metals. Scientific studies have heavily focused on finding suitable materials and techniques for the purification of wastewaters, but most solutions have been rejected due to cost-related issues. Several potential materials for this objective have been found and have been compared to determine the most suitable material for the purification process. Sawdust, among all the materials investigated, shows high potential and very promising results. Sawdust has been shown to have a good structure suitable for water purification processes. Parameters affecting the adsorption mechanism of heavy metals into sawdust have been studied and it has been shown that pH, contact time and several other parameters could play a major role in improving the adsorption process. The adsorption was found to follow the Langmuir or Freundlich isotherm and a pseudo second-order kinetic model, meaning that the type of adsorption was a chemisorption. Sawdust has major advantages to be considered and is one of the most promising materials to solve the wastewater problem.

Removal of Heavy Metals from Aqueous Solution by Hydroxyapatite/Chitosan Composite

2013 ◽  
Vol 789 ◽  
pp. 176-179 ◽  
Author(s):  
Eny Kusrini ◽  
Nofrijon Sofyan ◽  
Dwi Marta Nurjaya ◽  
Santoso Santoso ◽  
Dewi Tristantini
Keyword(s):  
Heavy Metals ◽  
Aqueous Solution ◽  
Metal Ions ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Removal Of Heavy Metals ◽  
Sem Micrograph ◽  
Pseudo Second Order ◽  
Chitosan Composite

Hydroxyapatite/chitosan (HApC) composite has been prepared by precipitation method and used for removal of heavy metals (Cr6+, Zn2+and Cd2+) from aqueous solution. The HAp and 3H7C composite with HAp:chitosan ratio of 3:7 (wt%) were characterized by Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy-energy dispersive X-ray spectroscopy. The SEM results showed that HAp is spherical-shaped and crystalline, while chitosan has a flat structure. SEM micrograph of 3H7C composite reveals crystalline of HAp uniformly spread over the surface of chitosan. The crystal structure of HAp is maintained in 3H7C composite. Chitosan affects the adsorption capacity of HAp for heavy metal ions; it binds the metal ions as well as HAp. The kinetic data was best described by the pseudo-second order. Surface adsorption and intraparticle diffusion take place in the mechanism of adsorption process. The binding of HAp powder with chitosan made the capability of composite to removal of Cr6+, Zn2+and Cd2+from aqueous solution effective. The order of removal efficiency (Cr6+> Cd2+> Zn2+) was observed.

Kinetics of Heavy Metals Adsorption on Gravels Derived From Subsurface Flow Constructed Wetland

2020 ◽  
pp. 193-213
Author(s):  
Celestin Defo ◽  
Ravinder Kaur
Keyword(s):  
Heavy Metals ◽  
Constructed Wetland ◽  
Contact Period ◽  
Batch Experiments ◽  
Removal Of Heavy Metals ◽  
Pseudo Second Order ◽  
Adsorption Rates ◽  
Kinetics Of ◽  
Best Fit ◽  
Concentration Levels

Adsorption kinetics of Ni, Cr, and Pb on gravels collected from constructed wetland was studied at varied metal concentrations and contact period for estimating the removal of heavy metals from wastewater. Batch experiments were conducted by shaking 120 ml of metal solutions having 5 concentration levels each of Ni (1.0, 2.0, 3.5, 5.0 and 6.0 mg l-1), Cr (1.0, 2.0, 3.0, 4.5 and 6.0 mg l-1), and Pb (1.0, 3.0, 6.0, 8.0 and 12.0 mg l-1) with 50 g of gravels for as function of time. Adsorption of Ni, Cr, and Pb on gravels ranged from 34.8 to 47.2, 42.7-54.9, and 47.5-56.9%, indicating their removal in the order: Pb > Cr > Ni. Freundlich model showed a good fit for Ni and Cr (R2>0.9) while Langmuir model fitted better for Pb (R2= 0.7). The pseudo-second-order model showed the best fit to simulate the adsorption rates of these metals on gravel.

Cadmium Adsorption Kinetic Study Using Natural Brasgel Clay the Adsorbent

2018 ◽  
Vol 912 ◽  
pp. 202-206 ◽  
Author(s):  
Joseane Damasceno Mota ◽  
Rochélia Silva Souza Cunha ◽  
Patrícia Noemia Mota de Vasconcelos ◽  
Meiry Gláucia Freire Rodrigues
Keyword(s):  
Heavy Metals ◽  
Industrial Effluents ◽  
Exchange Capacity ◽  
Adsorption Kinetic ◽  
Cadmium Removal ◽  
Kinetic Tests ◽  
Pseudo Second Order ◽  
Environmental Agencies ◽  
Best Fit ◽  
Nickel Lead

Heavy industrial activities result in contamination of waste water with many heavy metals, including cadmium, nickel, lead, mercury. Within this context becomes a growing concern of the population and environmental agencies regarding water contamination by heavy metals from industrial effluents. Because of this problem, this paper aims to study and evaluate the main properties of natural Brasgel clay in order to remove cadmium from synthetic effluents, analyzing its kinetic adsorption and its isothermal balance. Once clays exhibit good cation exchange capacity, selectivity and regenerability and for this reason has aroused interest in the use as an adsorbent. As finite bath testing we found that the Brasgel clay, removed approximately 90% of cadmium. The Langmuir model presented best fit to the experimental data, adequately describing the dynamics of adsorption. Kinetic tests indicated that the cadmium removal process by natural Brasgel clay apply the mechanism of the pseudo-second-order rate model, a time of 20 minutes and required to reach equilibrium. Thus, the results indicated that Brasgel clay can be used as an adsorbent for the removal of cadmium from contaminated effluent.

scholarly journals Polyaniline Modified with Cobalt-Hexacyanoferrate (PmCH) as an Adsorbent for Removal of Heavy Metals from Aqueous Solutions

2018 ◽  
Vol 51 ◽  
pp. 03004
Author(s):  
Nima Moazezi ◽  
Mohammad Ali Moosavian
Keyword(s):  
Heavy Metals ◽  
Ionic Strength ◽  
Aqueous Solutions ◽  
Metal Ions ◽  
Contact Time ◽  
Ion Concentration ◽  
Adsorption Capacities ◽  
Cobalt Hexacyanoferrate ◽  
Optimum Ph ◽  
Removal Of Heavy Metals

In this study, polyaniline modified with cobalt-hexacyanoferrate (PmCH) composite was synthesized and characterized for removal of Rb+, Cd2+, Zn2+, Pb2+, and Ni2+ by FTIR and XRD. The effect of pH, adsorbent dosage, ionic strength, contact time, initial ion concentration, and temperature were studied. The competition adsorption experiments between metal ions were investigated. Batch desorption was also conducted to evaluate the reusability of PmCH. The maximum adsorption capacities were 96.15, 27.17, 17.85, 19.15, and 4.76 mg g-1 of Rb+, Cd2+, Zn2+, Pb2+, and Ni2+, respectively. The optimum pH was determined at natural pH of each solution.

A review on polypyrrole-coated bio-composites for the removal of heavy metal traces from waste water

2019 ◽  
pp. 152808371987127 ◽  
Author(s):  
Subhankar Maity ◽  
Ashish Dubey ◽  
Supriyo Chakraborty
Keyword(s):  
Waste Water ◽  
Heavy Metals ◽  
Heavy Metal ◽  
Industrial Wastewater ◽  
Waste Water Treatment ◽  
Absorption Properties ◽  
Adsorption Capacities ◽  
Ion Absorption ◽  
Removal Of Heavy Metals ◽  
Day By Day

With the development of industrialization and human activities, discharge of waste water containing heavy metals in the environment is increasing day by day. It causes serious threats to the human civilization and the flora and fauna in this earth. Conducting polymers like polypyrrole and polyaniline can be used for treating wastewater due to their inherent ion absorption properties. This article has been focused on the development of polypyrrole coated bio-composites and their potential about the removal of heavy metals from industrial wastewater. Adsorption process can be successfully employed to remove heavy metals from the wastewater by the treatment of water with polypyrrole-coated composites. It was reported in literature that the polypyrrole and polyaniline-coated adsorbents had good adsorption capacities for Mg, Fe, Cu, Cd, Pb, Zn, and Ni. Polypyrrole-coated saw dust, rice husk, chitin, and cellulosic materials could be able to remove Cr, Fe, Cu, and Zn from wastewater. This method would be a replacement for costly conventional methods of removing heavy metal ions from wastewater. It is expected that this method would be an alternative for waste water treatment which will benefit the industries in future.

scholarly journals Immobilization of β-CD on a Hyper-Crosslinked Polymer for the Enhanced Removal of Amines from Aqueous Solutions

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1620
Author(s):  
Zujin Yang ◽  
Guifang Wu ◽  
Qiuru Li ◽  
Hongxia Ai ◽  
Xingdong Yao ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Interaction Mechanism ◽  
Industrial Effluents ◽  
Order Mode ◽  
Freundlich Model ◽  
Crosslinked Polymer ◽  
Adsorption Capacities ◽  
Pseudo Second Order ◽  
Polymeric Resins ◽  
Enhanced Adsorption

In this paper, we adopted a simple and efficient strategy to prepare a β-cyclodextrin (β-CD)-modified hyper-crosslinked polymer (CDM-HCP). The structures and physicochemical properties of the as-synthesized polymer were also evaluated. It was applied to the removal of anilines from aqueous solutions. The introduction of β-CD into the hyper-crosslinked polymer significantly enhanced adsorption properties for the removal of various amines. The adsorption kinetics agreed with the pseudo-second-order mode very well. The adsorption isotherm data of p-methylaniline (p-MA) and p-aminobenzoic acid (p-ABC) were in agreement with the Langmuir isotherm, whereas aniline and p-chloroaniline (p-CA) were fitted best with the Freundlich model. The maximum adsorption capacities (qmax) determined by adsorption isotherms were 148.97 mg/g for aniline, 198.45 mg/g for p-MA, 293.71 mg/g for p-CA, and 622.91 mg/g for p-ABC, respectively. It had higher adsorption capacities than those of some commercial polymeric resins, such as XAD-4, PA66, and AB-8. The interaction mechanism was investigated by FTIR, XPS, and the ONIOM2 method. A CDM-HCP can be regenerated efficiently and used repeatedly, indicating its potential technological applications in removing organic pollutants from actual industrial effluents.

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