Related Experiment Video
Updated: Aug 7, 2025
08:59
A Freeze-Thawing Method to Prepare Chitosan-Polyvinyl alcohol Hydrogels Without Crosslinking Agents and Diflunisal Release Studies
Published on: January 14, 2020
17.7K
Study on Flocculation Behavior of Cr(VI) Using a Novel Chitosan Functionalized with Thiol Groups.
Yuelong Zhao1, Peng Zhang1,2,3, Wei Zhang3,4
1College of Environmental Science and Engineering, Taiyuan University of Technology, Taiyuan 411201, China.
Polymers
|March 11, 2023
Summary
Chitosan-graft-thiol (CTS-GSH) effectively removes hexavalent chromium (Cr(VI)) from wastewater. This modified chitosan composite shows high efficiency, especially in acidic conditions, offering potential for heavy metal treatment.
Area of Science:
- Environmental Chemistry
- Materials Science
- Wastewater Treatment
Background:
- Hexavalent chromium (Cr(VI)) is a toxic heavy metal pollutant requiring effective removal methods.
- Chitosan (CTS) is a biocompatible polymer with potential for modification to enhance its adsorptive properties.
Purpose of the Study:
- To synthesize and characterize chitosan-graft-thiol (CTS-GSH) as a novel adsorbent for Cr(VI) removal.
- To evaluate the efficiency of CTS-GSH in removing Cr(VI) from aqueous solutions under various conditions.
Main Methods:
- CTS-GSH was synthesized by grafting thiol (-SH) groups onto chitosan (CTS).
- Characterization was performed using Fourier Transform Infrared (FT-IR) spectroscopy, Scanning Electron Microscopy (SEM), and Differential Thermal Analysis-Thermogravimetric Analysis (DTA-TG).
- Cr(VI) removal efficiency was assessed by varying CTS-GSH dosage, pH, stirring time, and in the presence of common ions.
Main Results:
- Successful grafting of -SH groups onto CTS, forming a porous CTS-GSH composite with a spatial network surface.
- CTS-GSH demonstrated high Cr(VI) removal efficiency, with nearly complete removal achieved at optimal conditions (pH 6, 100.0 mg/L CTS-GSH for 5.0 mg/L Cr(VI)).
- Maximum removal efficiency of 99.3% was observed with a stirring time of 8.0 min and sedimentation time of 3 h.
- Common ions (Mg2+, Ca2+, SO42-, CO32-) exhibited an inhibitory effect, requiring higher CTS-GSH dosages for effective removal.
Conclusions:
- CTS-GSH is a highly effective adsorbent for removing Cr(VI) from wastewater.
- The material's performance is influenced by pH, dosage, and the presence of interfering ions.
- CTS-GSH shows significant potential for practical applications in heavy metal wastewater treatment.
Related Concept Videos
01:09Colloidal precipitates
659
The high insolubility of some precipitates can result in an unfavorable relative supersaturation. This can lead to colloidal particles with a large surface-to-mass ratio, where adsorption is promoted. For instance, in the precipitation of silver chloride, silver ions are adsorbed on the surface of the colloidal particles, forming a primary layer. This layer attracts ions of opposite charge (such as nitrate ions), forming a diffuse secondary layer of adsorbed ions. This electric double layer...
659
01:06Coagulation
348
Colloidal solids are solid particles suspended in solution. They are usually negatively charged, attracting a compact primary layer of positively charged ions, which attract more counterions to form an electrical double layer. Electrostatic repulsion between the charged double layers prevents the particles from colliding, stabilizing the colloids. These solids are often undesirable because they can contain toxins that are difficult to remove. Coagulation is a technique that helps aggregate and...
348
02:33Preparation and Reactions of Thiols
6.5K
Thiols are prepared using the hydrosulfide anion as a nucleophile in a nucleophilic substitution reaction with alkyl halides. For instance, bromobutane reacts with sodium hydrosulfide to give butanethiol.
6.5K
01:23Factors Affecting Dissolution: Particle Size and Effective Surface Area
917
Dissolution kinetics, an essential aspect of oral drug delivery, is significantly influenced by the drug's particle size. According to the Noyes-Whitney dissolution model, the dissolution rate correlates directly with the drug's surface area. The larger the surface area, the higher the drug's solubility in water, leading to a faster drug dissolution rate. Reducing particle size increases the effective surface area, enhancing the dissolution process. Micronization and nanosizing are...
917
01:19Complexation Equilibria: The Chelate Effect
581
In complexation reactions, metal atoms or cations interact with ligands to form donor-acceptor adducts called metal complexes. Ligands that bind through one donor site are monodentate, ligands with two donor sites are bidentate, and those with more than two donor sites are polydentate ligands. For example, ethylene diamine is a bidentate ligand that binds through two nitrogen donor atoms, forming a five-membered ring. EDTA is a polydentate ligand that binds through four oxygen and two nitrogen...
581
01:17Colloids and Suspensions
1.9K
Children at play often make suspensions such as mixtures of mud and water, flour and water, or a suspension of solid pigments in water known as tempera paint. These suspensions are heterogeneous mixtures composed of relatively large particles visible to the naked eye or seen with a magnifying glass. They are cloudy, and the suspended particles settle out after mixing. The suspended particles in a suspension settle out after some time of mixing. The separation of particles from a suspension is...
1.9K