Zhitong Yao

Mechanical and thermal properties of polypropylene (PP) composites filled with modified shell waste.

Shell waste, with its high content of calcium carbonate (CaCO3) plus organic matrix, has a potential to be used as a bio-filler. In this work, shell waste was modified by furfural and then incorporated to reinforce polypropylene (PP). The shell waste and modified powder were characterized by means of X-ray diffraction (XRD), scanning electron microscopy equipped with an energy dispersive spectrometer (SEM-EDS), X-ray photoelectronic spectroscopy (XPS), and Fourier transformed infrared spectroscopy (FTIR). The mechanical and thermal properties of neat PP and PP composites were investigated as well. Thermal gravimetric (TG) analyses confirmed the reinforcing role of modified powder in PP composites. The mechanical properties studied showed that adding modified powder could significantly increase the impact strength, elongation at break point and flexural modulus of composites. The maximum incorporation content could reach 15 wt.% with a good balance between toughness and stiffness of PP composites. Differential scanning calorimetry (DSC) results showed that the modified powder could act as a nucleating agent and thus increase the crystallization temperature of PP. Polarized optical microscopy (POM) observation also indicated that the introduction of modified powder could promote the heterogeneous nucleation of PP matrix.

Bivalve Shell: Not an Abundant Useless Waste but a Functional and Versatile Biomaterial

Bivalve shells, available in abundance, have no eminent use and are commonly regarded as waste. Their improper disposal causes a significant level of environmental concern and also results in a waste of natural resources. Bivalve shell is formed by biomineralization and consists mainly of CaCO3 with a small amount of organic matrix, giving it a potential for use as raw material. Recycling shell waste could potentially eliminate the disposal problem, and also turn an otherwise useless waste into high value-added products. The present paper first describes the microstructure and physicochemical properties of bivalve shell, then focuses on its current applications. Finally, the current status of bivalve shell studies and directions for future research are considered.

Mechanical and thermal properties of polypropylene (PP) composites filled with CaCO3 and shell waste derived bio-fillers

The clam shell (CS) waste was first modified by furfural and hydrochloric acid to prepare fillers FCS and ACS, which were then used as fillers in polypropylene (PP), as well as the commercial calcium carbonate (CC). These fillers were characterized and analyzed by means of X-ray diffraction (XRD), atomic force microscopy (AFM), particle size analyzer, Fourier transformed infrared spectroscopy (FTIR) and contact angle measurement. The mechanical and thermal properties of PP composites were investigated as well. XRD analysis indicated that the major crystalline phase of CC was calcite; of shell waste derived fillers, calcite and aragonite. The CC was fully hydrophobic, while the shell derived fillers were amphiphilic. Mechanical property studies showed that the incorporation of FCS played the role mainly of toughening the PP; of CC, CS and ACS, that of reinforcing. The optimum filler contents of CS, ACS and FCS could reach 5, 7 and 15 wt.%, respectively, to obtain a good balance between fracture toughness and stiffness of the PP composites. Polarized optical microscopy (POM) observation indicated that the inclusion of these fillers could promote the heterogeneous nucleation of PP.

Remediation of 1,2,3-trichlorobenzene contaminated soil using a combined thermal desorption-molten salt oxidation reactor system.

A combined thermal desorption (TD)-molten salt oxidation (MSO) reactor system was applied to remediate the 1,2,3-trichlorobenzene (1,2,3-TCB) contaminated soil. The TD reactor was used to enrich the contaminant from soil, and its dechlorination of the contaminant was achieved in the MSO reactor. The optimum operating conditions of TD, and the effects of MSO reactor temperatures, additive amounts of the TCB on destruction and removal efficiency (DRE) of TCB and chlorine retention efficiency (CRE) were investigated. The reaction mechanism and pathway were proposed as well. The combined system could remediate the contaminated soil at a large scale of concentration from 5 to 25gkg(-1), and the DRE and CRE reached more than 99% and 95%, respectively, at temperatures above 850°C. The reaction emissions included C6H6, CH4, CO and CO2, and chlorinated species were not detected. It was found that a little increase in the temperature can considerably reduce the emission of C6H6, CH4, and CO, while the CO2 level increased.

Preparation, characterization, and antibacterial activity of shell waste loaded with silver

A green inorganic antibacterial material was prepared using shell waste as a carrier material loaded with silver. It was characterized and analyzed by X-ray diffraction (XRD), scanning electron microscopy equipped with an energy dispersive spectrometer (EDS), X-ray photoelectronic spectroscopy (XPS) and N2 adsorption isotherms. The antibacterial activity was evaluated using Staphylococcus aureus and Escherichia coli as sensitive indicator strains. The antibacterial mechanism was probed and discussed as well. Silver carbonate was detected in the prepared material through XRD analysis. XPS measurement and EDS analysis also confirmed the loading of silver onto the carrier. The antibacterial test demonstrated that the prepared material had good antibacterial property, especially against E. coli. Based on the silver ion release and pH test, as well as comparatively analyzing the characteristics of carrier material and prepared material, we proposed that the antibacterial mechanism mainly involved the antibacterial activity of silver ion, slightly higher pH value and supplementary photocatalytic antibacterial activity of silver carbonate.

Synthesis, characterization and sintering behaviour of indialite ceramic from fly ash

Indialite ceramic was prepared using fly ash and magnesium carbonate powder as precursors. The effects of sintering aids LiOHu2009·u2009H2O and TiO2 on its crystallization and morphology evolution were studied as well. X-ray diffraction results indicated that the formation of indialite was achieved by solid-state sintering reactions at 1200°C for 4u2009h. With increasing amounts of LiOHu2009·u2009H2O, the viscosity decreased and β-spodumene, spinel phases started to develop at the expense of indialite. Scanning electron microscopy observations revealed that the surface of the sintered samples became smoother with higher porosity losses and grain size reduction. As the TiO2 contents increased from 4 to 10%, dauphine-twinned quartz and rutile were formed by simultaneously consuming indialite. In this process, the viscosity showed no significant changes.