Good bioactivity and tunable mechanical properties of akermanite (Ca2MgSi2O7), as compared to calcium phosphate materials, have garnered increasing attention as a potential bone substitute material. Typically, these Ca-Mg-Si bioceramics are synthesised using commercially available chemicals. In this study, we aimed to transform clinical dental mould waste (DMW) into an alternative calcium source used in synthesising akermanite ceramics. The DMW were initially refined involving alkaline roasting and caustic leaching, resulting in high purity Ca(OH)2 powder. This Ca(OH)2 powder was then mixed with MgO and SiO2 in stoichiometric proportion and subsequently subjected to planetary ball milling, pressed into pellets and sintered at 1200-1250 degrees C, forming the desired akermanite ceramics. Two calcium sources were investigated: Ca(OH)2 refined from DMW and chemically available CaO. Comparative analyses between Akr-Ca(OH)2 and Akr-CaO confirmed that both types of akermanite ceramics exhibited akermanite as the major phase with a minor phase of diopside. Regardless of the calcium source used, the physical and mechanical properties of the akermanite produced improved with increasing sintering temperature. However, Akr-Ca(OH)2 possess relatively lower mechanical properties than Akr-CaO. These intriguing findings underscored the potential for utilising calcium derived from DMW in producing akermanite ceramics with acceptable mechanical properties. Utilising this sustainable approach to create akermanite ceramics for bone substitutes may indirectly alleviate environmental pollution. This is because dental mould waste (DMW), which contains small amounts of chromium that can leach out and harm soil quality when discarded into landfills, is minimised. Furthermore, this innovative method shows potential for providing an affordable bone substitute option for patients in need.

Copper smelting slag (CSS) are waste slag obtained from smelters after reusing sulphur smelting slag. This study explores the potential of CSS to serve as a resource in cement mortar construction. Specifically, the study investigates the use of mechanical and chemical methods to enhance the volcanic ash activity of CSS, enabling them to replace up to 30 % of the cement content in cement mortar. The modified CSS was analyzed in terms of particle size and (Toxicity Characteristic Leaching Procedure) TCLP testing, while cement mortar specimens were subjected to a battery of tests including compressive strength, Freeze-thaw experiment, TCLP testing and cement stability testing. The results showed that compared with the unmodified CSS material, the copper smelting slag cement material with CaCO3 3 meets the requirements of GB/T 1596-2017 on the standard compressive strength of OPC 42.5 grade, with a compressive strength of 38.88 MPa at 10 % CaCO3 3 admixture, among which the CSS cement material with 10 % CaCO3 3 is the best and meets the leaching toxicity standard. Moreover, the modified CSS reduced energy consumption by 7.15 %, CO2 2 emissions by 27.41 %, and cost by 19.84 %. XRD, FTIR and SEM analysis showed that the mechanical activation of CaCO3 3 doping more drastically damaged the crystal structure of CSS, and local lattice distortion occurred, which induced the transformation of CSS from crystalline phase to amorphous phase and destroyed the ordered structure of minerals, resulting in the volcanic ash activity increased. Overall, this study demonstrates that CSS can serve as a viable raw material in cement mortar samples, reducing environmental impact and achieving resourceful use of slag.

Meeting agricultural requirements without a significant impact on the soil-water ecosystem in terms of delivering agrochemicals for seed germination and plant growth necessitates the development of a sustainable and multifunctional controlled release fertilizer carrier. For this purpose, the current study aims at fabricating highly porous urea-biochar/PLA-based agro-augmenting bead-free electrospun mats (EM) with improved physicomechanical performance. The method involved the hydrothermal synthesis of walnut shell-derived biochar, followed by the ball milling, urea loading and subsequent incorporation of urea-loaded ball-milled biochar into porous PLA-based electrospun fibers. The impacts of ball milling and urea loading were evaluated by using morphological (FESEM and TEM), microstructural (FTIR and XRD), and physiochemical (BET and BJH) attributes. To enhance the surface hydrophilicity, PLA-based porous EM was fabricated by altering the concentration of cosolvent (DCM:DMSO) and relative humidity (20-80%). Bead-free and uniform urea/biochar-loaded PLA EM were fabricated by incorporating urea/biochar into PLA precursor solution, and the resultant EM showed improved surface hydrophilicity (with a contact angle of 98.4 degrees), water absorption (similar to 69.4%), retention capacity (similar to 17days), and effective release of urea in water (similar to 11.6%) and soil (similar to 5.67%). The thermal stability (degradation temperature from 334 to 413 degrees C) and mechanical properties (from similar to 9.6-13.56 MPa) are improved for PLA-based EM upon incorporating urea-biochar. The efficacy of developed EM for promoting plant growth was validated by conducting germination and growth assessments using green gram (Vigna radiata) plants. The results demonstrated a higher germination rate (59.33%), plant height (23.67 cm), root length (9.33 cm), dry weight (0.38g), and fresh weight (0.44g) for plants treated with the EM as compared to the control sample. Thus, the study established optimally designed uniform bead-free microfibrous electrospun constructs with tunable urea release, pointing at an agrotechnology not only enhancing crop yield but also ensuring environmental sustainability as undesirable nutrient-induced secondary complications such as eutrophication and soil quality deuteriation possibilities are largely mitigated.