A New System of Sustainable Silico-Aluminous and Silicate Materials for Cultivation Purpose within Sustainable Buildings: Chemical-Physical, Antibacterial and Cytotoxicity Properties

Abstract

In this study, we compared the chemical-physical, antibacterial, and cytotoxicity properties of silico-aluminous and silicate materials for outdoor (green roof, planted walls) and indoor (urban farms, indoor microgreen gardens) cultivation purpose in a context of sustainable construction. Glasses and lightweight aggregates were tailored starting from waste, by-product, and post-consumer and bioproducts (packaging glass cullet, cattle bone flour ash, vegetable biomass ash, spent coffee ground, degreased from biomass of prepupae of Black Soldier Flies) mixed together with a national ferruginous red clay, quarry scrap pumice and, if necessary, with K2CO3 of reagent grade. The first type of material was obtained by melting at 1200 °C and the second one by powder sintering at 1000 °C. All specimens, subjected to antibacterial test, showed both low zone of inhibitions towards two Gram-negative and two Gram-positive bacterial strains. A cytotoxicity test on mouse embryonic fibroblast NIH-3T3 cell line directly exposed to the investigated materials was performed at three different exposure times (1 h, 3 h, and 6 h). Data acquired highlighted that the materials positively affected redox mitochondrial activity of the fibroblast cells. The concentrations of leachate heavy metals detected on selected materials in water at room temperature after 24 h were lower than the European law limit and an interesting release of P, K, and N nutrients was noted for those formulations designed for agronomic purposes. pH, falling on average within the 6.5–7.5 range, is optimal for most crops, and the specific conductivity <2 dS/m indicates no depression danger for crops. Both bulk density <1200 kg/m3 and porosity over 50% seem to ensure good performance of lightening, drainage, water reservation, and oxygenation of the roots.

Suitability of Porous Inorganic Materials from Industrial Residues and Bioproducts for Use in Horticulture: A Multidisciplinary Approach

“…Spent coffee grounds, for example, have a neutral pH, therefore, it has been added in previous studies to neutralize the pH of PIMs that used other alkaline poring agents, such as biochar [28]. Fertilizer glass (FG), on the other hand, does not appear to affect the pH of PIMs, even though it has an alkaline pH [6]. The results obtained showed that the use of pumice scraps in the matrix instead of clay had a positive effect on the porosity of the granules, with values around 50% for Appl.…”

“…pH of PIMs that used other alkaline poring agents, such as biochar [28]. Fertilizer glass (FG), on the other hand, does not appear to affect the pH of PIMs, even though it has an alkaline pH [6]. The results obtained showed that the use of pumice scraps in the matrix instead of clay had a positive effect on the porosity of the granules, with values around 50% for APV50, increasing the value as compared to the porosity of PIMs consisting only of clay (43%) reported by Andreola et al [13].…”

“…In the context of circular economy and circular engineering, two phases of the change in the waste management paradigm and two compositions of porous inorganic materials (PIMs) were selected from a range of compositions previously tailored by the authors [6]. The contribution of silico-aluminate and silicate was provided by clay, as a natural raw material, and by the scraps from the extraction of pumice, the latter transformed in the form of both ceramic and glass matrix.…”

Effects of LED Lights and New Long-Term-Release Fertilizers on Lettuce Growth: A Contribution for Sustainable Horticulture

“…For this research, the aggregates were obtained in the form of a core-shell specimen by formulating an NPK supply system of spent coffee ground, bone ash, and defatted biomass from black soldier fly prepupae. These lightweight materials were designed and customized to provide nutrients over a period of time [18][19][20] Horticultural activities can be carried out indoors, for example, in kitchen gardens, with many advantages. First, there is no seasonality or extreme weather conditions to hinder crop growth, and it allows for the efficient use of resources, such as water and fertilizers, that can be applied according to the crop's specific needs.…”

Recycling of Waste Corundum Abrasive Powder in MK-Based Geopolymers

“…MK spectrum shows the Si-O-T (T = Si or Al) bands at 1080 cm −1 . This peak is also recognized as DOSPM (Density of State Peak Maximum) and could be used to follow the geopolymerization [ 18 , 21 , 27 ]. Indeed, this band shifts to a lower wavenumber (1019–1014 cm −1 ) suggesting the increase of Si-O-Al bonds.…”