Synthesis and characterisation of acid/basic modified adsorbents. Application for chlorophenols removal

2021 ◽  
pp. 112187
Author(s):  
Joaquín R. Domínguez ◽  
Carlos J. Durán-Valle ◽  
Germán Mateos-García
Keyword(s):  
Modified Adsorbents

scholarly journals Optimization of cadmium(II) adsorption onto modified and unmodified lignocellulosics (rice husk and egussi peeling)

2015 ◽  
Vol 5 (1) ◽  
pp. 45
Author(s):  
Tchuifon Tchuifon Donald Raoul ◽  
Nche George Ndifor-Angwafor ◽  
Ngakou Sadeu Christian ◽  
Kamgaing Théophile ◽  
Ngomo Horace Manga ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Rice Husk ◽  
Order Kinetic ◽  
Adsorption Model ◽  
Batch Technique ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Adsorbed Quantity ◽  
Minimal Mass ◽  
Modified Adsorbents

<p>The present study is based on the adsorption of cadmium (II) ions on rice husk and egussi peeling, unmodified and modified with nitric acid in aqueous solution, using batch technique. It was carried out as a function of contact time, dosage, pH and initial concentration. The equilibrium time was achieved within 25 minutes for unmodified rice husk (Glu NT) and 20 minutes for unmodified egussi peeling (Cuc NT) with an adsorbed quantity of 13.18 mg/g. In the case of modified materials, we obtained 15 minutes for modified rice husk (Glu HNO3) and 10 minutes for modified egussi peeling (Cuc HNO3) with an adsorbed quantity of 18.77 mg/g. The maximum biosorption occurred at pH 5.5 for all biosorbents. The adsorbent mass for maximum adsorption was 0.4 g giving an adsorption capacity of 62.02 % for unmodified adsorbents. In the case of modified adsorbents, the minimal mass at which maximum adsorption occurred was 0.4 g giving an adsorption capacity of 98.33 % and 0.6 g giving an adsorption capacity of 98.33 % for modified rice husk and egussi peeling respectively. The adsorbent/adsorbate equilibrium was well described by the pseudo-second order kinetic model and by Langmuir’s and Freundlich adsorption model. This models showed that the adsorption of cadmium (II) is a chemisorption process.</p>

scholarly journals Simultaneous removal of cationic and anionic dyes from aqueous solution by double functional groups modified bagasse

2020 ◽  
Vol 82 (10) ◽  
pp. 2159-2167
Author(s):  
Ru-yi Zhou ◽  
Jun-xia Yu ◽  
Ru-an Chi
Keyword(s):  
Aqueous Solution ◽  
Functional Groups ◽  
Order Kinetic ◽  
Anionic Dyes ◽  
Adsorption Capacities ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Amine Groups ◽  
Modified Adsorbents ◽  
Zeta Potential Analysis

Abstract Double functional groups modified bagasse (DFMBs), a series of new zwitterionic groups of carboxyl and amine modified adsorbents, were prepared through grafting tetraethylenepentamine (TEPA) onto the pyromellitic dianhydride (PMDA) modified bagasse using the DCC/DMAP method. DFMBs' ability to simultaneously remove basic magenta (BM, cationic dye) and Congo red (CR, anionic dye) from aqueous solution in single and binary dye systems was investigated. FTIR spectra and Zeta potential analysis results showed that PMDA and TEPA were successfully grafted onto the surface of bagasse, and the ratio of the amount of carboxyl groups and amine groups was controlled by the addition of a dosage of TEPA. Adsorption results showed that adsorption capacities of DFMBs for BM decreased while that for CR increased with the increase of the amount of TEPA in both single and binary dye systems, and BM or CR was absorbed on the modified biosorbents was mainly through electrostatic attraction and hydrogen bond. The adsorption for BM and CR could reach equilibrium within 300 min, both processes were fitted well by the pseudo-second-order kinetic model. The cationic and anionic dyes removal experiment in the binary system showed that DMFBs could be chosen as adsorbents to treat wastewater containing different ratios of cationic and anionic dyes.

scholarly journals Evaluation of modified montmorillonite with di-cationic surfactants as efficient and environmentally friendly adsorbents for arsenic removal from contaminated water

2017 ◽  
Vol 18 (2) ◽  
pp. 460-472 ◽  
Author(s):  
E. Shokri ◽  
R. Yegani ◽  
B. Pourabbas ◽  
B. Ghofrani
Keyword(s):  
Contact Time ◽  
Arsenic Removal ◽  
Environmentally Friendly ◽  
Contaminated Water ◽  
X Ray Diffraction ◽  
Solution Ph ◽  
Modified Montmorillonite ◽  
Adsorption Capacities ◽  
Modified Adsorbents ◽  
Adsorption Desorption

Abstract In this work, montmorillonite (Mt) was modified by environmentally friendly arginine (Arg) and lysine (Lys) amino acids with di-cationic groups for arsenic removal from contaminated water. The modified Mts were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, zeta potential and thermal analysis. The adsorption of As(V) onto modified Mts as a function of initial As(V) concentration, contact time and solution pH was investigated. The removal efficiency was increased with increasing the As(V) concentration and contact time; however, it was decreased with increasing solution pH. The maximum As(V) adsorption capacities of Mt-Arg and Mt-Lys were 11.5 and 11 mg/g, respectively, which were five times larger than pristine Mt. The high adsorption capacity makes them promising candidates for arsenic removal from contaminated water. The regeneration studies were carried out up to 10 cycles for both modified Mts. The obtained results confirmed that the modified adsorbents could also be effectively used for As(V) removal from water for multiple adsorption – desorption cycles.

Kinetics, equilibrium and thermodynamics of dyes adsorption onto modified chitosan: a review

2021 ◽  
Vol 235 (11) ◽  
pp. 1499-1538
Author(s):  
Abida Kausar ◽  
Kashaf Naeem ◽  
Munawar Iqbal ◽  
Zill-i-Huma Nazli ◽  
Haq N. Bhatti ◽  
...  
Keyword(s):  
Dye Adsorption ◽  
Thermodynamic Characteristics ◽  
Modified Chitosan ◽  
Chemical Structures ◽  
Highly Efficient ◽  
Adsorption Capacities ◽  
Variable Chemical ◽  
Modified Adsorbents ◽  
Dyes Adsorption

Abstract In view of promising sorption capacity, stability, biodegradability, cost-effectiveness, environmental friendly nature, regeneration and recycling ability, the chitosan (CS) based adsorbents are highly efficient for the sequestration of dyes. Since CS offers variable chemical structures and CS have been modified by incorporating different moieties. The CS composites with unique properties have been employed successfully for dye adsorption with reasonably high adsorption capacity versus other similar adsorbents. Modifications of CS were promising for the preparation of composites that are extensively studied for their adsorption capacities for various dyes. This review highlights the CS and its modification and their applications for the adsorption of dyes. The removal capacities of CS-based adsorbents, equilibrium modeling, kinetics studies and the thermodynamic characteristics are reported. Moreover, the FTIR, BET, SEM, TGA and XRD were employed for the characterization of CS modified adsorbents are also discussed. Results revealed that the modified CS is highly efficient and can be employed for the sequestration of dyes from effluents.

scholarly journals Adsorption of Cr(VI), Pb(II) Ions and Methylene Blue Dye from Aqueous Solution using Pristine and Modified Coral Limestone

2020 ◽  
Vol 32 (10) ◽  
pp. 2624-2632
Author(s):  
C.S. Nkutha ◽  
N.D. Shooto ◽  
E.B. Naidoo
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Freundlich Isotherm ◽  
Blue Dye ◽  
Methylene Blue Dye ◽  
Sorption Behaviour ◽  
Freundlich Model ◽  
Experimental Parameters ◽  
Acid And Base ◽  
Modified Adsorbents

This work reports the feasibility of using pristine and chemically modified coral limestones by acid and base. Their potential adsorptive capabilities is probed by treatment of toxic Cr(VI), Pb(II) ions and methylene blue in aqueous solution under different experimental parameters by batch method. Parameters such as agitation time, concentration, temperature and pH were varied to understand the sorption behaviour of the adsorbents in each case. The adsorbents were characterized by SEM, XRD and FTIR. Morphological analysis by SEM micrographs show that the surface of all adsorbents was irregular in nature. XRD spectra confirmed the orthorhombic structure of aragonite in the pristine coral limestones (PCL), acid modified coral limestones (ACL) and base modified coral limestones (BCL). FTIR results affirmed the presence of (CO3 2-) and (-C=O) groups of the carbonate ions and Ca-O attachment to the surface of PCL and removal of CaCO3 characteristic peaks in ACL and BCL. However, in the modified adsorbents shifting of Ca-O peaks occurred. The recorded maximum adsorption capacities of PCL, ACL and BCL for Cr(VI) ions were 69.42, 65.04, 64.88 mg/g, Pb(II) ions 39.36, 74.11, 78.34 mg/g and methylene blue 37.24, 46.28, 46.39 mg/g, respectively. The uptake of Pb(II), Cr(VI) ions, methylene blue onto PCL fitted Freundlich model. Also the uptake of Cr(VI) ions and methylene blue onto ACL and BCL fitted Freundlich isotherm. However, uptake of Pb(II) ions onto both ACL and BCL fitted Langmuir isotherm. The data revealed that the adsorption of Pb(II) ions onto PCL and ACL and methylene blue dye onto PCL was exothermic. Whilst the adsorption of Cr(VI) ions onto PCL, ACL and BCL and methylene blue dye onto ACL and BCL were endothermic in nature, hence increasing the temperature would enhance the uptake of Pb(II) ions onto BCL, Cr(VI) ions onto ACL and BCL and methylene blue onto ACL and BCL. The obtained (ΔGº) values at all studied temperatures for the adsorption of Pb(II), Cr(VI) ions and methylene blue onto PLC, ACL and BCL indicated a spontaneous process.

scholarly journals Recent Advancements in the Removal of Cyanotoxins from Water Using Conventional and Modified Adsorbents—A Contemporary Review

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2756
Author(s):  
Tauqeer Abbas ◽  
George William Kajjumba ◽  
Meena Ejjada ◽  
Sayeda Ummeh Masrura ◽  
Erica J. Marti ◽  
...  
Keyword(s):  
Water Treatment ◽  
Human Exposure ◽  
Future Outlook ◽  
Environmental Pressures ◽  
Treatment Processes ◽  
Current Review ◽  
Recent Developments ◽  
Modified Adsorbents ◽  
Design Simplicity ◽  
A Current

The prevalence of cyanobacteria is increasing in freshwaters due to climate change, eutrophication, and their ability to adapt and thrive in changing environmental conditions. In response to various environmental pressures, they produce toxins known as cyanotoxins, which impair water quality significantly. Prolonged human exposure to cyanotoxins, such as microcystins, cylindrospermopsin, saxitoxins, and anatoxin through drinking water can cause severe health effects. Conventional water treatment processes are not effective in removing these cyanotoxins in water and advanced water treatment processes are often used instead. Among the advanced water treatment methods, adsorption is advantageous compared to other methods because of its affordability and design simplicity for cyanotoxins removal. This article provides a current review of recent developments in cyanotoxin removal using both conventional and modified adsorbents. Given the different cyanotoxins removal capacities and cost of conventional and modified adsorbents, a future outlook, as well as suggestions are provided to achieve optimal cyanotoxin removal through adsorption.

scholarly journals A Comparison Study of Mechanism: Cu2+Adsorption on Different Adsorbents and Their Surface-Modified Adsorbents

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Yaqin Yu ◽  
Xinrui Li ◽  
Jiemin Cheng
Keyword(s):  
Carbon Black ◽  
Adsorption Mechanism ◽  
Environmental Fate ◽  
Physical Adsorption ◽  
Hexadecyltrimethylammonium Bromide ◽  
Significant Implication ◽  
Isothermal Adsorption ◽  
Oxidized Carbon ◽  
Modified Adsorbents ◽  
Organic Bentonite

The isothermal adsorption kinetics of Cu2+onto Carbon Black (CB) and Oxidized Carbon Black (OCB) were studied under different solution conditions and compared with bentonite and organic bentonite with the hexadecyltrimethylammonium bromide (HDTMA). The adsorption capacities followed the order of OCB > CB > organic bentonite > bentonite, which was consistent with the orders of their surface roughness and specific surface area. The Fourier transmission infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscope (TEM) were used to explore the adsorption mechanism at molecular level. The adsorption process onto CB was physical adsorption. However, with the increase of oxygen-containing functional groups (C=O, C-O, and CNO), the chelation adsorption onto OCB became gradually dominant except physical adsorption. The ion exchange adsorption was the major adsorption mechanism of bentonite. The compounds were introduced into clay interlayer by complexing reaction with Cu2+, which improved the adsorption capacity of organic bentonite. The results present a significant implication for the environmental fate assessment of heavy metal pollution.

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