In Situ Synthesis and Characterization of ZnO/Chitosan Nanocomposite as an Adsorbent for Removal of Congo Red from Aqueous Solution
Nhu Thanh Nguyen, Ngoc Thinh Nguyen, Van Anh Nguyen
Abstract
ZnO/chitosan nanocomposite was successfully synthesized by in-situ precipitation method. The material was characterized by XRD, FESEM, TEM, FTIR, BET, and TGA. Results show that ZnO/chitosan nanocomposite has spherical shape with the average size of 20–25 nm. BET surface area and the average pore size of ZnO/chitosan nanocomposite are 2.2436 (m 2 /g) and 12.2 nm, respectively. The material was applied as an adsorbent for congo red removal from aqueous solutions. The congo red adsorption is better described by the Langmuir model (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mrow><mml:msup><mml:mrow><mml:mi>R</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msup><mml:mo>=</mml:mo><mml:mn>0.996</mml:mn></mml:mrow></mml:math>) than by the Freundlich model (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mrow><mml:msup><mml:mrow><mml:mi>R</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msup><mml:mo>=</mml:mo><mml:mn>0.962</mml:mn></mml:mrow></mml:math>). Therefore, it can be presumed that congo red was adsorbed in a single monolayer with the theoretical maximum adsorption capacity of 227.3 (mg/g). This is comparable to other available adsorbents. It can be suggested that ZnO/chitosan nanocomposite could serve as promising adsorbent for congo red in wastewater treatment technology.