Green Waste-Derived Substances Immobilized on SBA-15 Silica: Surface Properties, Adsorbing and Photosensitizing Activities towards Organic and Inorganic Substrates

Abstract

Urban wastes are a potential source of environment contamination, especially when they are not properly disposed. Nowadays, researchers are finding innovative solutions for recycling and reusing wastes in order to favour a sustainable development from the viewpoint of circular economy. In this context, the lignin-like fraction of biomass derived from Green Compost is a cost-effective source of soluble Bio-Based Substances (BBS-GC), namely complex macromolecules/supramolecular aggregates characterized by adsorbing and photosensitizing properties. In this work BBS-GC were immobilized on a silica support (SBA-15) and the chemico-physical properties of the resulting hybrid material (BBS-SBA) were analysed by zeta-potential measurements, nitrogen adsorption at 77K and micro-calorimetric techniques. Successively, the BBS-SBA photosensitizing and adsorption abilities were tested. Adsorption in the dark of Rhodamine B and Orange II on BBS-SBA and their degradation upon irradiation under simulated solar light were shown, together with the formation of hydroxyl radicals detected by Electron Paramagnetic Resonance spectroscopy. Furthermore, the adsorption of six inorganic ions (Al, Ni, Mn, As, Hg, Cr) on BBS-SBA was studied in pure water at two different pH values and in a landfill leachate, showing the good potential of this kind of materials in the removal of wastewater contaminants.

The Innovation Comes from the Sea: Chitosan and Alginate Hybrid Gels and Films as Sustainable Materials for Wastewater Remediation

“…It is made of water soluble macromolecules with a complex lignin-derived structure containing acid (i.e., carboxylic groups) and basic functional groups (i.e., amino group) bonded to aromatic and aliphatic chains, plus a portion of ashes (a similar structure found in a previous work [30] is reported in Scheme 1C) [29,31]. The large amount of freely available functionalities makes BBS-GC an interesting adsorption promoter, as already demonstrated in previous studies on other systems [32,33].…”

“…The BBS-GC IR spectrum ( Figure 2, curve A) presented signals at ca. 3400 cm −1 ascribable to O-H stretching mode and a weak signal at 2925 cm −1 due to C-H stretching mode; carboxylic and amide groups (symmetric stretching vibrations of C=O) were present at 1630 cm −1 , whereas signals at 1420 cm −1 were correlated to C-H bending and/or O-C-O stretching of carboxylate groups; signals at 1034 cm −1 were due to C-O-C stretching and/or aryl-bonded C-H bending [32].…”

SBA-15 Anchored Metal Containing Catalysts in the Oxidative Desulfurization Process

“…SBA-15 has been applied in a large variety of industrial processes after functionalization with active species on both the bulky silica framework or on the surface of the material [13][14][15]. These processes include: (i) oxidative transformation of hydrocarbons, such as alkanes [16,17], alkenes [18,19] and aromatic derivatives [20,21]; (ii) oxidative transformation of alcohols [22]; (iii) CO oxidation [23]; reduction processes [24] Knoevenagel reactions [25]; waste water treatments [26,27]; and carrier applications in drug-delivery [28,29].…”

Simultaneous Catalysis of Sulfite Oxidation and Uptake of Heavy Metals by Bifunctional Activated Carbon Fiber in Magnesia Desulfurization

“…However, a magnesium desulfurization slurry that contains heavy metal impurities cannot be treated using conventional alkaline precipitation because a large amount of magnesium would precipitate prior to the heavy metals. If the porous adsorption properties of cobalt-based catalysts can be used to simultaneously remove heavy metals in the catalytic oxidation process of magnesium sulfite, the purity of the magnesium desulfurization by-products can be significantly improved and the secondary pollution of heavy metals can be reduced, which has significant economic and environmental benefits.Currently, adsorbents used for treating heavy metals in wastewater mainly include porous materials such as activated carbon, carbon nanotubes, metal organic framework (MOF), SBA-15 Silica (SBA, Santa Barbara Amorphous), Calcium Alginate/Graphene and vermiculite-based hydrated zirconia [19][20][21][22][23]. Li et al [24] synthesized a thiol-functionalized activated carbon material from coal-blended sewage sludge, and the material was found to achieve the highest Brunauer-Emmett-Teller (BET) surface area of 1094 m 2 /g when maintained under 500 • C for 30 min.…”

“…Currently, adsorbents used for treating heavy metals in wastewater mainly include porous materials such as activated carbon, carbon nanotubes, metal organic framework (MOF), SBA-15 Silica (SBA, Santa Barbara Amorphous), Calcium Alginate/Graphene and vermiculite-based hydrated zirconia [19][20][21][22][23]. Li et al [24] synthesized a thiol-functionalized activated carbon material from coal-blended sewage sludge, and the material was found to achieve the highest Brunauer-Emmett-Teller (BET) surface area of 1094 m 2 /g when maintained under 500 • C for 30 min.…”