Abstract
In this study, the Pb(II) adsorption capabilities of the heavy metal tolerant strain of fungus, Aspergillus piperis, were studied. This study involved finding optimal growth conditions using a plating technique, and optimal adsorption conditions using submerged fermentation and fractional factorial experimental design. The adsorption behaviour was then elucidated using isotherm and kinetic models, of which the one surface Langmuir isotherm provided the best fit, with a maximum predicted adsorption capacity of 275.82 mg g−1. The kinetic models suggested that internal mass transfer is the driving force behind the reaction rate. After adsorption, biomass surface characterisation was undertaken using FESEM, EDS, and ATR-FTIR to explain observations. The system was characterised by a cation exchange mechanism with strong carboxyl and organophosphorus group interactions. This study demonstrates that due to the ease of propagation and high adsorption capacity, this locally sourced fungal strain is an ideal adsorbent for industrial Pb(II) bioremediation.
Highlights
Lead (Pb) is a highly toxic, bioaccumulative substance that can cause adverse effects in humans
By studying radial mycelium growth and batch fermentation conditions, Aspergillus piperis has shown the capacity to grow under a variety of conditions which makes it easy to propagate in ordinary environments
The adsorption isotherm and kinetic data can readily be described by the Langmuir isotherm, pseudo-first order, two phase PFO, and Langmuir kinetic models
Summary
Lead (Pb) is a highly toxic, bioaccumulative substance that can cause adverse effects in humans. The permissible blood serum Pb level for a child is 5 μg dL−1 [1] and values higher than this have been associated with hearing loss, lowered intelligence, aggression, and violent behaviour [2], while acute exposure can result in organ failure and death. Pb products like leaded paint and petrol have largely been phased out in most of the world [3], contamination still arises from industries such as mining and battery processing plants. In South Africa human exposure is often associated with informal industries like illegal gold mining, battery salvaging, and the use of Pb sinkers for subsistence fishing [4]. Industrial water treatment commonly utilises carbonate or hydroxide treatment because the Pb can be recovered through filtration, but this method is expensive and requires long retention times [7]. More recently new techniques have been developed whereby remediation is carried out via biologically active compounds
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
