Nuclear chemistry

Adsorption

Iron oxide

BET theory

Langmuir adsorption model

Organic chemistry

Endothermic process

Manganese

Langmuir

Fly ash

Chemistry

Microporous and Mesoporous Materials

Heavy metals are becoming a huge problem in the environment and lead is one of them. Lead is disposed into water systems from huge industries such as paint industry, mining, and electroplating. In this study, manganese oxide coated fly ash (MnO2-CFA) was synthesized and characterized. The BET surface area of CFA MnO2-CFA was 18.4196 m2/g, 3 times more than the raw CFA (5.9231 m2/g). Batch adsorption experiments indicated that the uptake of Pb2+ fitted well in a Elovich kinetics model while the adsorption isotherm best fitted the Langmuir model with a maximum adsorption capacity of 141 mg/g at 40 °C and a pH of 7. Thermodynamic parameters obtained proved that the adsorption of Pb2+ ions using the MnO2-CFA was endothermic and spontaneous. Furthermore, the adsorbent was highly selective towards Pb2+ in the presence of Mn2+, Zn2, Ni2+and Cd2+. The Pb2+ removal % from a real water sample spiked with 30 mg/L Pb2+ was found to be 83.33%. The spent adsorbent was further applied in latent fingerprint detection which showed that Pb2+-MnO2-CFA produced clearer latent finger print (LFP) images compared to MnO2-CFA. LFP images were still clear 8 days after application of the spent adsorbent, proving that Pb2+-MnO2-CFA is a promising labelling agent.

Preparation of manganese oxide coated coal fly ash adsorbent for the removal of lead and reuse for latent fingerprint detection