Oilothermal, a novel pyrolysis method for fabrication of carbon dots-loaded carriers from cyanobacteria for use in solid-phase extraction of cadmium

Abstract

BackgroundMaking carbon dots-loaded carriers (CLCs) required the use of two types of precursors (one for carrier particles and the other for carbon dots) and at least three steps. In this study, CLCs were fabricated by using cyanobacterial cells as a dual-purpose precursor and oilothermal as an innovative pyrolysis method. MethodsThe oilothermal method allowed that each cyanobacterial cell (carrier particle precursor) with its hydrous exopolysaccharides (EPSs) layer (carbon dots precursor) to be encapsulated together by an oil micelle and pyrolyzed separate from other cells and formed the CLC in one step. The potential of emerging CLCs for solid-phase extraction (SPE) was assessed. For this purpose, the CLCs were tested in a cadmium-based model. Significant findingsThe range of the maximum pH-dependent adsorption efficiency (>95%) was extensive (pH 4–10). The adsorption kinetics and isotherm had the best fit with the pseudo-second-order and Langmuir linear models, respectively. The adsorption capacity was 5305.61 mg kg−1 only in 2 min exposure time. The findings in this research conclude that emerging CLCs, because of their unique features such as high capacity, fast adsorption rate, fast recovery rate, green origin, optimal and efficient fabrication method, have a high potential for SPE of trace cadmium.