Optimization of bio-cement production from cement kiln dust using microalgae

• Published in: Biotechnology reports (Amsterdam, Netherlands) Netherlands), 2019-09, Vol.23, p.e00356, Article e00356
• Main Authors: Irfan, M.F., Hossain, S.M.Z., Khalid, H., Sadaf, F., Al-Thawadi, S., Alshater, A., Hossain, M.M., Razzak, S.A.
• Format: Article
• Language: English
• Subjects: Bio-cement; CaCO3 precipitation; Microalgae; Optimization; Waste management
• ISSN: 2215-017X; 2215-017X
• DOI: 10.1016/j.btre.2019.e00356

[Display omitted] •CKD with microalgae sp. Chlorella kessleri is investigated for maximum bio-cement yields.•A predictive quadratic model was developed for CaCO3 yield with R2 value of c.a. 92%.•Low temperature and high pH were found to be important parameters in RSM study.•Under optimal set, a maximum of 96% Ca was extracted experimentally from CKD.•FTIR, XRD and EDS analysis confirmed the produced bio-cement compound. The main aim of this study was to maximize bio-cement (CaCO3) production through a waste feedstock of cement kiln dust (CKD) as a source of calcium by deployment of microalgae sp. Chlorella kessleri. The effect of process parameters such as temperature, pH and time-intervals of microalgae cultivation, were set as criteria that ultimately subscribe to a process of optimization. In this regard, a single factor experiments integrated with response surface methodology (RSM) via central composite design (CCD) was considered. A quadratic model was developed to predict the maximum CaCO3 yield. A ceiling of 25.18 g CaCO3 yield was obtained at an optimal set of 23 °C, pH of 10.63 and day-9 of microalgae culture. Under these optimized conditions, maximum 96% calcium was extracted from CKD. FTIR, XRD and EDS analyses were conducted to characterize the CaCO3 precipitates. Compressive modes of mechanical testing seemed to hold conventional cement complimented by CaCO3 co-presence markedly superior to mere cement performance as far as compressive strength is concerned. The latter criterion exhibited further increase in correspondence with rise in cement to bio-cement ratio. This investigative endeavour at hand offers a simple pivotal platform on the basis of which a scale-up of microalgae-infested bio-cement production might be facilitated in conjunction with the added benefit of alleviation in environmental pollution through cement waste utilization.