https://nova.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 Influence and mechanisms of active silica in solid waste on hydration of tricalcium aluminate in the resulting composite cement https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:39251 2) which can be used as supplementary cementitious material (SCM) to replace part of Portland cement. Existing studies mainly focus on the impact of solid waste on tricalcium silicate (C3S) hydration. Since tricalcium aluminate (C3A) is the most reactive component of the Portland cement, it is of great interest t to investigate the effect of solid waste containing SiO2 on the hydration process of C3A. In this study, different amounts of nano-silica (nano-SiO2) were mixed with C3A and the hydration products after 72 h of hydration were analyzed by means of X-ray diffraction (XRD), Fourier Transform Infrared analyzer (FT-IR), Environment Scanning Electronic Microscope - Energy Dispersive Spectrometer (ESEM-EDS), X-ray Photoelectron Spectroscopy (XPS) and Solid-state Nuclear Magnetic Resonance (NMR). The results showed that nano-SiO2 can promote the hydration of C3A and stabilize the hydration products of C3A in the form of crystalline hydrogarnet (C3AH6). The formation of Si-O-Al bonds was also found in the hydration products. ESEM results revealed that the surface of the crystalline hydration products (C3AH6 particles) was covered by gel-like products. The results from the XPS and NMR analyses further confirmed that the negatively charged nano-SiO2 and the silicate anions can literally interact with C3A to produce calcium silicoaluminate hydrate (C-A-S-H) gel, whereas the formation of C-A-S-H is attributed to the substitution reaction of Al in the Si-O-Si network occurring on the surface of C3A. In addition to the reactive silica-aluminum component reacting with Ca(OH)2 to form additional calcium silicate hydrate (C-S-H) and C-A-S-H gels, the reactive silicon in solid waste can also undergo pozzolanic reaction with C3A to form C-A-S-H gel.]]> Tue 09 Aug 2022 14:10:52 AEST ]]> Fixation of carbon dioxide and optimization of liming process waste produced in tanneries using response surface methodology https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:42576 95% of calcite (CaCO₃) recovery from synthetic lime wastewater followed by 85-90% from LSP & RSP under optimized conditions. Subsequent reduction of total dissolved solids and suspended solids in the range of 78-82% and 76-77% in LSP & RSP was also observed. Mineralogical analysis using X-ray diffraction technique along with standards (lime, calcite, lime & calcite mix) confirms the production of calcite. Statistical analysis showed a P value < 0.05 indicating a higher degree of correlation (R₂ > 0.95) among the process conditions and variables using response surface methodology and was further validated using artificial neural networking. This study demonstrates a sustainable and cleaner way of resource recovery from waste through CO₂ fixation from lime solid waste (sludge).]]> Thu 25 Aug 2022 15:17:59 AEST ]]> Kinetic and isotherm insights of Diclofenac removal by sludge derived hydrochar https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:47951  0.9). The Diclofenac adsorption on hydrochars followed Langmuir isotherm model with the post-activated hydrochar recording a highest adsorption capacity of 37.23 mg g-1 in 40 mg L-1 initial Diclofenac concentration at 15 h equilibrium time.]]> Mon 13 Feb 2023 13:53:00 AEDT ]]> Chromium adsorption on surface activated biochar made from tannery liming sludge: A waste-to-wealth approach https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:51549 Fri 08 Sep 2023 15:06:57 AEST ]]>