Chitosan Composites Synthesized Using Acetic Acid and Tetraethylorthosilicate Respond Differently to Methylene Blue Adsorption

Abstract

The sol-gel and cross-linking processes have been used by researchers to synthesize silica-based nanostructures and optimize their size and morphology by changing either the material or the synthesis conditions. However, the influence of the silica nanostructures on the overall physicochemical and mechanistic properties of organic biopolymers such as chitosan has received limited attention. The present study used a one-step synthetic method to obtain chitosan composites to monitor the uptake and release of a basic cationic dye (methylene blue) at two different pH values. Firstly, the composites were synthesized and characterized by Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD) to ascertain their chemical identity. Adsorption studies were conducted using methylene blue and these studies revealed that Acetic Acid-Chitosan (AA-CHI), Tetraethylorthosilicate-Chitosan (TEOS-CHI), Acetic Acid-Tetraethylorthosilicate-Chitosan (AA-TEOS-CHI), and Acetic Acid-Chitosan-Tetraethylorthosilicate (AA-CHI-TEOS) had comparatively lower percentage adsorbances in acidic media after 40 h, with AA-CHI adsorbing most of the methylene blue dye. In contrast, these materials recorded higher percentage adsorbances of methylene blue in the basic media. The release profiles of these composites were fitted with an exponential model. The R-squared values obtained indicated that the AA-CHI at pH ~ 2.6 and AA-TEOS-CHI at pH ~ 7.2 of methylene blue had steady and consistent release profiles. The release mechanisms were analyzed using Korsmeyer-Peppas and Hixson-Crowell models. It was deduced that the release profiles of the majority of the synthesized chitosan beads were influenced by the conformational or surface area changes of the methylene blue. This was justified by the higher correlation coefficient or Pearson’s R values (R ≥ 0.5) computed from the Hixson-Crowell model. The results from this study showed that two of the novel materials comprising acetic acid-chitosan and a combination of equimolar ratios of acetic acid-TEOS-chitosan could be useful pH-sensitive probes for various biomedical applications, whereas the other materials involving the two-step synthesis could be found useful in environmental remediation of toxic materials.

Mechanical and Structural Characterization of Pineapple Leaf Fiber

“…Sustainable green technology developments have been elevated in recent times, especially, in the polymer composite industry [1]. Thus, the focus currently is on the identification and characterization of plant fibers for a variety of applications, including fabrication of scaffolds for tissue regeneration, drug delivery, and prosthetic design [2][3][4]. Plant fibers have been shown to be good potential alternatives to synthetic fibers from petroleum-based non-renewable sources [5].…”

Síntese de compósito a base de quitosana e sílica para adsorção de corante têxtil

“…Conforme Repo et al (2011), picos em torno de 1090-1060 cm -1 representam as vibrações Si-O-Si e Si-O-C da formação da rede estruturada do material. As diferenças nas intensidades dos picos dos compostos, indicam a modificação físico-química da quitosana para a formação do material com a rede de sílica (ESSEL et al, 2018;COPELLO et al, 2014).…”

“…Segundo Jiang et al (2018) a modificação da quitosana resulta em materiais adsorventes com uma melhor organização estrutural que favorece a adsorção devido a exposição dos sítios ativos, nesse caso os grupamentos aminas. Nesse estudo, isso pode ter ocorrido através das moléculas do percursor, que se ligaram aos monômeros da quitosana, aumentando sua área superficial e facilitando o acesso aos grupamentos amina (ESSEL et al, 2018). Portanto, a união de um adsorvente com outros materiais através dos métodos de modificação como reticulação, enxerto e a formação de compósitos, resulta em materiais com melhores propriedades de adsorção do que os efeitos dos componentes individuais (AUTA et al, 2014).…”

Physico-Chemical Properties of a Hybrid Biomaterial (Pva/Chitosan) Reinforced With Conductive Fillers

“…Polyvinyl alcohol (PVA) is a material with good structural properties but poor mechanical properties. That is why it is frequently reinforced with chitosan (Cs), which, in addition to improving the mechanical properties of the material, has amino (-NH2) groups, which makes its charge more positive [3][4][5][6][7][8][9]. Recent discoveries associated with conductive polymers have generated great interest recently.…”