Effect of Aluminium Powder on Kaolin-Based Geopolymer Characteristic and Removal of Cu2.

Nurliyana Ariffin,Przemysław Postawa,Agata Śliwa,Marcin Nabiałek,Mohd Firdaus Omar,Katarzyna Błoch,Shayfull Zamree Abd Rahim,Mohd Remy Rozainy Mohd Arif Zainol,Jerzy J Wysłocki,Ramadhansyah Putra Jaya,Mohd Mustafa Al Bakri Abdullah

doi:10.3390/ma14040814

Abstract

This current work focuses on the synthesis of geopolymer-based adsorbent which uses kaolin as a source material, mixed with alkali solution consisting of 10 M NaOH and Na2SiO3 as well as aluminium powder as a foaming agent. The experimental range for the aluminium powder was between 0.6, 0.8, 1.0 and 1.2wt%. The structure, properties and characterization of the geopolymer were examined using X-Ray Diffraction (XRD), Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Adsorption capacity and porosity were analysed based on various percentages of aluminium powder added. The results indicate that the use of aluminium powder exhibited a better pore size distribution and higher porosity, suggesting a better heavy metal removal. The maximum adsorption capacity of Cu2+ approached approximately 98%. The findings indicate that 0.8% aluminium powder was the optimal aluminium powder content for geopolymer adsorbent. The removal efficiency was affected by pH, adsorbent dosage and contact time. The optimum removal capacity of Cu2+ was obtained at pH 6 with 1.5 g geopolymer adsorbent and 4 h contact time. Therefore, it can be concluded that the increase in porosity increases the adsorption of Cu2+.

Highlights

Copper is one of the heavy metals that is hazardous to human health and the environment [1,2]
Kaolin fulfilled the requirement as a precursor of raw material for the manufacturing of the geopolymer
This is due to the fact that materials in forming of geopolymer should be rich in Si and Al as important sources of Si4+ and Al3+ in binding system that will be activated by alkali activator solution [56,57,58]

Summary

Introduction

Copper is one of the heavy metals that is hazardous to human health and the environment [1,2]. The descriptor heavy metal applies to any metal or metalloid material with a density between 3.5 and 7 g/cm3 [3,4,5]. This type of metal is commonly found in the Earth’s crust and is non-biodegradable. Zeolites have been widely used as an adsorbent in treating heavy metal because of their effectiveness in adsorbing contaminants [15,16]. They are extensively used for heavy metal removal from wastewater. The high cost of its production at the industrial level requires new, cheaper and less energy-consuming material

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Conclusion