Design and synthesis of chemically-modified biosorbents for the removal of anionic metals and dye

: Kinetic and thermodynamic studies

  • Zhouyang Huang

Student thesis: Masters ThesisMasters

Abstract

With the rapid development of modern industry. Environmental pollution caused by industry is becoming increasingly serious. Heavy metal ions and some kinds of dyes in industrial wastewater are key to pollution. How to eliminate harm of heavy metals and dyes and effectively recover them is a prominent problem that current environment protection works need to solve.
Biological adsorption as a new method of heavy metal and dyes removal and recovery, it has the advantages of wide source of raw materials, high adsorption efficiency, environmental friendliness, no secondary pollution and so on, showing a good application prospect. This paper mainly studies and discusses two kinds of bioadsorbent materials, natural banana peel and modified banana peel, as adsorbent. The adsorption properties and mechanism of heavy metal chromium (VI) and methylene blue dyes in wastewater adsorbed by natural banana peel and modified banana peel are studied respectively.

The detailed work is as follows:

1 The adsorption properties of two bioadsorbents, natural banana peel and modified banana peel, on chromium heavy metal and methylene blue solution were compared. The effects of reaction time, temperature, initial concentration and amount of adsorbent on the adsorption effect were investigated by adsorption experiment, and the adsorption thermodynamics and kinetics were also studied.

2 The specific surface area, surface structure and morphology of banana peel before and after modification were characterized by modern analytical techniques, such as BET-N2 adsorption method, infrared spectrum analysis, CHNS, SEM and X-RD The adsorption behavior of Cr (VI) in aqueous solution by banana peel biological adsorbent before and after modification was studied in detail. Low solution pH value was conducive to the removal of Cr (VI) in aqueous solution by adsorbent, and the adsorption process was accompanied by Cr (VI) reduction to Cr (III). The results of adsorption kinetics showed that the adsorption kinetics of banana peel before and after modified at different temperatures were more in line with pseudosecond-order kinetic equation. The adsorption isotherm results showed that the adsorption of Cr (VI) by banana peel bioadsorbent before and after modification was in line with the Langmuir monolayer adsorption model.

By studying the adsorption behavior of banana peel bioadsorbent before and after modified on methylene blue in aqueous solution in detail, when the pH value is higher than 6, it is more beneficial to the removal of methylene blue in aqueous solution by the adsorbent, but the adsorption efficiency tends to be stable. The results of adsorption kinetics showed that the adsorption kinetics of banana
peel before and after modified at different temperatures were more in line with pseudo-second-order kinetic equation. The adsorption isotherm results showed that the adsorption of methylene blue by banana peel bioadsorbent before and after modification was in line with the Langmuir monolayer adsorption model By measuring the release amount of Na+ and Mg2+ in the adsorption process, as well as the results of infrared spectrum and X-RD analysis, it is shown that the ion exchange mechanism is dominant in the adsorption of metal ions and methylene blue by modified banana biological adsorbent.

The adsorption data of Cr (VI) and methylene blue by banana peel before and after modification were obtained by this project. This study has economic and environmental significance for the
utilization of resources and provides a new idea for the deep utilization of biological waste. It also lays a good foundation for developing efficient and low-cost industrial wastewater treatment technology.
Date of AwardJul 2020
Original languageEnglish
Awarding Institution
  • Queen's University Belfast
SupervisorChirangano Mangwandi (Supervisor) & Bo Xiao (Supervisor)

Keywords

  • Chromium ion (VI)
  • Methylene blue
  • biosorption
  • banana peel
  • chemical modification

Cite this

Design and synthesis of chemically-modified biosorbents for the removal of anionic metals and dye: Kinetic and thermodynamic studies
Huang, Z. (Author). Jul 2020

Student thesis: Masters ThesisMasters