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The aim of this research was to evaluate the production of glass ceramics from novel combinations of fly ash, glass cullet, blast furnace slag and copper slag solid wastes. The CaO/SiO2 molar ratios of the mixtures were 0.17–0.39. Glass ceramics were produced by thermal treatment of frits obtained by quenching in water. The results show that samples with a high Fe2O3 content (>4 wt%) are not adequate for glass-ceramic formation, as a result of the effect of ferric iron, Fe3+, which increases the network connectivity, on the stability of the glass. The mechanical properties of the ceramic materials were as follows: elastic modulus of 97.8–106 GPa, Vickers microhardness of 612–701 MPa, fracture toughness of 0.45–0.84 MPa m1/2, and friction coefficient of 0.57–1.0. For the glass ceramics, the mass loss did not exceed 1% in NaOH and 15% in HNO3 as a result of the crystalline phases formed. The ceramic materials developed in this research could be considered for potential applications in the production of glazes for residential or industrial tiles and coatings, among others.

Foamed glass preparation is a complex combination of reactions, greatly influenced by the composition of the used glass and often hindered by simultaneous crystallization. The crystallization phenomenon is undesirable in foamed glass production since it decreases the quality of the final product. In this work the influence of different types of additives (foaming agents, flux agents, crystallization inhibitors and nucleating agent) on the crystallization of waste container glass and properties of the sintered samples (density and thermal conductivity) was studied. Results of our study confirmed partial crystallization during sintering stage. We found that waste container glass manifests complex crystallization with the formation of four main crystalline phases, which can be inhibited with the addition of fluxing agents (B2O3 and borax). Moreover, here we show that prevention of the crystallization can lead to a significant decrease of the thermal conductivity.

Incineration is the most common way to reduce the mass and the volume of municipal solid wastes. One of the most dangerous by-products of the incineration process is fly ash that contains a considerable amount of heavy metals. Therefore, its treatment is crucial to prevent the leaching of heavy metals into the environment. In the present work, two different sources of municipal solid waste incinerator fly ash have been vitrified in order to inhibit the release of potentially toxic heavy metals. Two different sources of silica, i.e. silica sand and glass cullet, have been added to each type of fly ash in an attempt to obtain vitrifiable batches. The standard leaching test on vitrified products was performed according to EN12457-2 confirming no heavy metal leaching and, therefore, they all pass waste acceptance criteria to be classified as an inert material. Furthermore, the previously reported data for vitrification of fly ash was combined with the present work and their compositions were presented in the SiO2–Al2O3–CaO, and SiO2-ΣM2O3-Σ(MO + M2O) ternary phase diagrams to identify the region in which successful compositions are concentrated. This analysis could facilitate the attempt to find the right composition for vitrification of fly ash.

Secondary grinding was investigated as a mean of liberating glass from locked particles of glass and resin obtained by the primary shredding from the silicon-based PV panels. Many previous studies on separating glass from resin have focused on chemical processes. However, a simple physical process—using an eccentric stirring mill to selectively grind the glass, separating the glass from the resin, and concentrating the glass into a narrower particle size group—resulted in successful liberation. Grinding rate analysis using the population balance model quantitatively confirmed that glass particles were more easily ground than resin particles and that locked particles were more easily ground than free particles. This is because the high specific gravity of the glass particles and the greater adhesiveness of the locked particles cause them to be located near the stirring blade of the mill. The selectivity of grinding became more significant and the grinding time shorter as the rotation speed increased. At the optimal grinding speed of 2500 rpm, 97% of the glass was concentrated into particles under 5.6 mm in size in 5 min. The resulting glass particles had a carbon content of 1% or less, which makes them suitable for the manufacture of glass fiber.

Researchers have shown that recycled materials can be used to substitute some of the mixture components in Ultra-High-Performance Concrete (UHPC) to result in more sustainable building material. One common material that can be recycled to be used in concrete applications is waste glass (WG). This paper presents a literature review on the effects on the fresh and hard mechanical properties of UHPC by recycled waste glass (WG). With the addition of recycled glass, the new material “Ultra-High-Performance Glass Concrete” (UHPGC) becomes extremely workable and possesses rheological characteristics improving fresh concrete behavior due to the low water absorption, smooth surface, and optimized package density of the material. The use of GP (Glass Powder) as a partial cement substitute in UHPGC gives good mechanical characteristics as compressive strength, tensile strength, and bending strength. In addition, the glass powder reduces the penetrability of chloride-ion in concrete and reduces the possibility of chloride-induced steel corrosion. The glass powder’s provide pozzolanic activity. In addition, UHPGC can be designed with a reduced amount of cement as the cement industry is one of the sources emitting CO2.

Cellulose fibre based insulation can be employed to maintain comfortable indoor conditions inside buildings and to improve energy efficiency. The huge energy consumption for space cooling can be decreased by applying cellulose fibre as thermal insulation in the buildings because of its low thermal conductivity. Cellulose fibre insulation is made from recycled paper fibres and inorganic additives are used to prevent mould growth and increase fire resistance. Here an effort has been made to examine the suitability of cellulose fibre as an insulation for buildings under static, dynamic heat transfer conditions, embodied energy and environmental pollution aspects are also examined. Cellulose fibre insulation has lower value of embodied energy and environmental impact as compared to other insulation materials. Cellulose fibre has lower embodied energy than the conventional and unconventional insulation materials. Cellulose fibre can be utilized in the buildings for maintaining a steady humidity value in the indoor air. Cellulose fibre board has the mean thermal conductivity equivalent to materials like cork, polyurethane, recycled glass, recycled cotton and glass wool. The cellulose fibre board has incredibly low mean thermal diffusivity than other materials like cork, polyurethane, recycled glass, recycled cotton and glass wool. Consequently cellulose fibre has similar thermal performance under static heat transfer conditions to the best insulation materials and the thermal performance of cellulose fibre for insulating buildings under dynamic heat transfer conditions will be much better than other insulation materials. Cellulose fibre is also environment friendly, renewable, recyclable and has lower embodied energy.

Generally in shops, damaged glass sheets & sheet glass cuttings are go to waste, which are not recycled at present and usually delivered to landfills for disposal. Glass powder used in concrete making leads to greener environment. Glass waste powder creates chronic environmental problems, mainly due to the inconsistency of waste glass streams. Glass is widely used in our day by day activities like in the products such as sheet glass, bottles, glassware, and vacuum tubing. Glass is an ideal material for recycling. The use of recycled glass helps in energy saving. In many research works aims to give awareness of glass recycling and save the environment. One of its significant contributions is to the construction field where the waste glass was reused for concrete production. In the current research work the properties of concrete with glass dust waste as fine aggregate were investigated. Glass dust waste was used as a partial replacement for sand at 10%, 20% and 30% of concrete mixes. Compression strength, split tensile strength and flexural strength for 7, 14 and 28 days concrete of age were compared with those of concrete made with natural fine aggregates. From this experimental work it was proven that increasing strength has been observed when replacing of glass waste powder by natural sand.

This paper reports the PIXE-PIGE data obtained at AGLAE accelerator on 135 glass beads discovered at Sarata Monteoru and Bratei, Romania, dated to 6th-7th centuries AD. The stylistically similar glass beads were excavated in two cemeteries situated 300 km apart, attributed to different populations. The Sarata Monteoru beads were found in incineration graves assigned to a Slavic population, while the Bratei beads were discovered in inhumation tombs pertaining to a Gepidic population. PIXE-PIGE data indicated that most glass beads were manufactured in Roman tradition, sharing a resembling chemistry. The compositional patterns of several items suggest glass recycling practices. A single bead was manufactured exclusively using plant ashes, pleading for its Oriental provenance. PIXE data provided clues about the glass chromophores. This archaeometric study demonstrates the connections between the populations living in the Carpathian area during the Migration Period with the Roman zones of influence.

The objective of this study was to evaluate the effect of ZnO content on the physical, mechanical and chemical properties of CaO–Al2O3–SiO2 (CAS) glass-ceramics produced from Colombian wastes, such as fly ash, granulated blast furnace slag and glass cullet. The CaO/SiO2 molar ratio of the mixtures was held constant (0.36). ZnO was added to the mixtures in proportions of 4, 7 and 10 wt%. The glass-ceramics were produced by the controlled crystallization of a parent glass. The values of crystallization temperature (Tp) show a fall up to 7 wt% and then shoots up with 10 wt% concentration of ZnO, but in general, ZnO addition lowers the temperature required for the formation of crystalline phases. In general, anorthite (CaAl2Si2O8) is the main phase observed in all heat treated samples, in addition to albite (Na(AlSi3O8)) and labradorite (Na0.45 Ca0.55 Al1.55 Si2.45 O8). The crystalline phases hardystonite (Ca2ZnSi2O7) and willemite (Zn2SiO4) were also identified in the samples with 7 and 10 wt% ZnO. The densities of the glass-ceramics were between 2658 and 2848 kg/m3, and it was found that ZnO helps to increase the density of glass-ceramics. The elastic modulus was in the 100–105 GPa range, the fracture toughness was between 0.45 and 0.64 MPa m1/2, and the Vickers microhardness was between 632 and 653 MPa. With regards to the durability, the weight loss of the glass-ceramics immersed in alkaline solution (NaOH) did not exceed 1.5 wt% after immersion for 6 h at 80 °C. The results of this study confirm that the vitrification process is a favorable option to utilize these industrial wastes.

Recycling and reusing of Fiber-reinforced polymer (FRP) composite is gaining a major attraction. In this study, the recycling process is achieved by subjecting the discarded FRP composite materials to the high-temperature environment, which leads to decomposing of thermoset matrix yielding only the fibers. These recycled glass fibers are used in terms of discontinues fibers as reinforcement in polymeric composites. But the strength and quality of the obtained recycled glass fiber composite are lower. It is also inevitable that the interface/interphase of FRP composites plays a vital role in governing their properties and performance. With respect to this, the present article focuses on the mechanical performance of neat epoxy, randomly oriented discontinuous glass fiber/epoxy (RODGE) composite, Carbon nanotube reinforced RODGE (CNT-RODGE) composite, and Functionalized Carbon nanotube reinforced RODGE (FCNT-RODGE) composite. The results revealed that FCNT-RODGE composite possessed the highest tensile and flexural strength, followed by CNT-RODGE, RODGE, and neat epoxy composite. This can be attributed to strong interfacial bonding, which in turn results in better stress transfer. Thermal characterization using Differential Scanning Calorimetry (DSC) was also conducted to obtain the glass transition temperature (Tg) of all the composites experimented in this study. It showed that CNT-RODGE composite had the lowest Tg value. Fractography of the fractured samples was also analysed by Scanning Electron Microscope (SEM) micrographs. It revealed the results which were in good agreement with the tensile characteristics.

The increased generation of demolition waste has led to the successful implementation of its utilization in civil engineering projects. The combination of recycled aggregates and supplementary materials can potentially improve the quality of geomaterials when constructing alternative railway capping layers. In this research, two types of demolition waste, namely, Recycled Concrete Aggregates (RCA) and Crushed Brick (CB), were studied in comparison to two Conventional Capping Materials (CCMs), which are currently used for railway track construction. Recycled Glass (RG) and Mixed Recovered Plastic (MRP) were also blended with RCA to assess their performance. All the materials and mixtures were evaluated in terms of both stiffness and strength. A new Repeated Load Triaxial (RLT) testing protocol was introduced based on the stress induced in the capping layers to determine the stiffness of the materials. A comparison was made among the current resilient modulus prediction models to find a model that would better fit the results for the demolition waste and mixtures. Multistage triaxial tests were also conducted to determine the strength, friction, stiffness and energy absorption capacity of the materials. It was found from this research study that RCA, CB and mixtures of RCA with RG and MRP have equivalent or higher levels of stiffness and strength than CCMs and are suitable alternatives for sustainable railway capping layer construction.

The safe disposal of nuclear waste is a key factor restricting the sustainable use of nuclear energy. Exploring safe and reliable disposal methods for nuclear waste has become a research hotspot. In this paper, cullet-based glass (CBG) was chosen as a new immobilization agent to host the plutonium (Pu). The immobilization mechanism of Pu in the CBG was investigated by using cerium (Ce) as a surrogate for Pu, and the interaction was characterized by using XRD, XPS, FTIR and SEM-EDS analyses. The results indicate that there are two synergistic immobilization mechanisms by which Ce is hosted in the vitrified products. One mechanism is doping of the Ce into the crystal lattice of the glassy matrix to form Ce O Si bonds, which increases the proportions of non-bridging oxygen (NBO) bonds in the glass structure. The other mechanism is Ce co-existing in the glass structure gaps as individual crystals of CeO2. The synergistic immobilization makes Ce hard to release. The PCT results show that the normalized leach rate of Ce decreases with the Ce partitioning ratio in the CeO2 crystalline phase. These data show that CBG can be used as a good immobilization agent to vitrify the Pu presented in high-level radioactive wastes.

This study aimed at developing an eco-friendly precast concrete product by enhancing the application of waste glass. The waste glass was utilized as both fine aggregates and a partial binder in the form of glass powder (GP) in the paving blocks. The results showed that the strength was constant despite increasing amount of glass cullet (GC) was used in the paving blocks. The combined use of GC and fine GP was beneficial in reducing the water absorption and drying shrinkage of the paving blocks within permissible limits. Moreover, the addition of GP could successfully address the concern of ASR expansion resulting from GC.

This study designed an eco-friendly pervious concrete (PC) product using waste glass cullet (WGC) and recycled concrete aggregate (RCA) by dry-mixed compaction technique. The mechanical properties, water permeability behavior and related pore structure characteristics, thermal conductivity of the PCs were determined. The experimental results showed that the use of silica fume in the cement paste was effective to compensate for the low compressive strength of the PCs due to the use of narrowed graded aggregates without the incorporation of fine particles (less than 2.36 mm). Although the incorporation of recycled aggregates (i.e. WGC and RCA) into the PCs led to reductions in compressive strength, the water permeability of the PCs was improved, especially for the PCs prepared with WGC, as the use of WGC was conducive to improving the water permeability due to the negligible water absorption nature and smooth surface of glass cullet. Another encouraging result indicated that the PCs comprising 50% WGC as the fine aggregate and 50% RCA as the coarse aggregates could achieve satisfactory strength and permeability, which could largely meet the requirement of the standard (JIS A 5371) for permeable pedestrian pavers. The appropriate blending of the selected size of WGC (2.36–5 mm) and RCA (5–10 mm) to produce a desirable pore structure in the PCs were responsible for the good performance. In addition, the low thermal conductivity of the produced PCs provided an opportunity to use the PC as partition block materials for saving energy consumption of buildings.

The environmental and accessibility concerns associated with the increasing use of river sand in construction have diverted the attention of scientists to alternative materials. Waste glass has been widely investigated as a replacement for sand in geopolymer concretes, and the chemical and mechanical properties of the resulting materials are investigated. Since glass is rich in amorphous silica, it is believed that the surface of glass aggregates can take part in the reaction and make a stronger geopolymer matrix compared to that of sand aggregates. An improvement of 30% in compressive strength was obtained by replacing sand aggregates with glass aggregates. While the mechanical properties support interfacial reaction with glass aggregates, the nature of the chemical bonding structure at the interface has not been revealed. In this research, synchrotron Fourier transform infrared (SR-FTIR) microspectroscopy has been used for the first time to map the distribution of the chemical bonding structures at the geopolymer interface with aggregates. While in-situ FTIR shows the development of geopolymer gel over time, SR-FTIR results show clear differences in gel chemistry around the glass compared to the sand. The study reveals that there is a relatively higher degree of silica-rich gels close to the sand aggregates and a higher extent of geopolymeric gels around glass aggregates. The alkaline content of glass makes the area surrounding the glass aggregates more suitable for maintaining monomeric silica. These small silica species help to develop a higher degree of geopolymer networks in the vicinity of the glass aggregates compared to the sand. This level of visibility is very useful for understanding the behaviour of geopolymer concretes, which is critically important for nano-engineering of materials towards a desirable distribution of the binding gels.

Waste glass cullet (WGC) recovered from almost all waste streams is contaminated with mixed-color sources of variable compositions. Consequently, over 60% of the cullet is discarded in landfills in North America. The present work provides an overview of the potential end markets for the cullet with a focus on collection systems, marketing strategies, safety and environmental issues as well as the economics of the target applications. Cullet can find major applications in construction industry as a substitute to natural aggregates integrated with different proportions of concrete to build pavements, and roads Cullet could be widely used in different applications due to its desirable physical, mechanical, and chemical properties. This makes cullet an appropriate alternative for natural resources. Although various applications discussed in this paper have well-established markets, low proportion of cullet has been implemented in those applications. This could be attributed to the higher preprocessing cost of cullet compared to the natural aggregates. Different measures are required by the governments to continue to develop the potential post-consumer markets for recycled cullet such as encouraging recycling of WGC and restricting the use of landfilling activities for WGC.

Novel ceramic foams have been prepared by high temperature sintering of waste mineral wool and waste glass using SiC as a foaming agent. The aim of the research was to understand the effects of composition and sintering conditions on the properties and microstructure and produce commercially exploitable ceramic foams. Optimum ceramic foams were formed from 40 wt% mineral wool waste and 2 wt% SiC, sintered at 1170 °C using a heating rate of 20 °C/min with a 20 min hold at peak temperature. The ceramic foams produced had a bulk density of 0.71 g/cm3 and a uniform pore size distribution. The research shows that ceramic foams can be formed from waste mineral wool and these can be used for thermal insulation with associated economic and environmental benefits.

In light of concerns relating to improper waste disposal and resources preservation, reclamation of the discarded glass in construction materials had been extensively carried out since 1963. In the past decade, although more than 100 papers associated with the use of glass powder (GP) in the micron level scale were published, comprehensive review of all practical applications in cement-based materials and construction products is not available. This paper therefore provides a summary of the body of knowledge on the interaction and effects of using GP in cement-based and extended construction materials. This review concludes that GP is an innovative and promising eco-supplementary cementitious material. Beyond that, use of GP is demonstrated to be potentially beneficial as a precursor in geopolymer and suitable for manufacturing eco-cement, artificial lightweight aggregate and composite phase change material. The multiple applications of GP are seen as an important step towards waste glass recycling as a sustainable construction material and for the overall betterment of the industry.

The presented paper is based on a comparative experimental study aimed to incorporate coarse recycled concrete aggregates (RCA) and coarse recycled glass aggregates (RGA) from waste glass “windshield” in the composition of self-compacting concrete (SCC). The main objective is to study the influence of these aggregates on fresh and hardened concrete properties. In order to reach this purpose, two series of SCC mixes were prepared by replacing natural coarse aggregates (NCA) by RCA and RCA by RGA. The key properties of SCC recommended by European specifications and guidelines (EFNARC), were measured in the fresh state. While the compressive strength, water absorption testing and the observations on cross-section to evaluate the stability and segregation potential, were conducted on hardened concretes. For replacement of NCA by RCA, the use in SCC fine and coarse recycled concrete aggregates is not advisable, the flowability criteria cannot be ensured. The experimental results showed that the slump flow test has given a diameter of 610 mm. Likewise, also the L-box blocking ratio was limited to 0.2. The replacement of RCA by RGA did not significantly affect the initial slump, the obtained values are all above the minimum threshold of 650 mm. EFNARC criterion of passing ability is also satisfied. The yield stress and the plastic viscosity, determined by empirical equations, are in agreement with those observed with traditional SCC. The compressive strength of the RGA–SCC mixes decreased with an increase in recycled glass content but remain within the strength range of self-compacting concretes. The results have showed that it is possible to produce SCC with windshield waste glass aggregates.

This paper shows the potential benefits of using recycled glass fines as a sustainable and low-cost alternative compared to fly ash, silica fume and fine sand in concrete foam. One of the main concerns of using recycled glass in concrete is durability and particularly alkali-silica reaction (ASR). SEM-EDS analysis of the mortar with glass showed the formation of ASR gel with a higher silicon to calcium ratio around the glass particles which justified the large ASR expansion. On the other hand, microtomography analysis showed that the porous structure of concrete foam can accommodate the expansion of ASR gel inside the pores with considerably less expansion and no cracking. The majority of the pores filled with ASR gel are at the outer edge of the sample which was in contact with the alkaline solution. The smaller pores are more likely to be filled with ASR gel compared to the larger pores. Replacement of 10 wt% of Portland cement with milled glass resulted in higher strength compared to the other cementitious materials because of better compaction within the binder and pore strengthening effect due to rearrangement of pore sizes, as well as reduction of the unit weight. Recycled glass slightly decreased water absorption but substantially reduced the drying shrinkage of concrete foam.

Fly ash and glass cullet - two materials, which are produced in quite large amounts. This paper presents the new way the high calcium fly ash (HCA) and the industrial glass waste powder (GP) disposal in building materials technology as main components of binders. Samples were examined over the period up to 6 years of maturity. There were used only two kinds of waste materials (GP + HCA) and water to produce pastes. Fine grinded glass was used as alkaline activator. The HCA was used to induce alkaline activation and dissolution of the glass powder in HCA – GP mixtures. Materials were mixed in three different proportions to prepare the samples. The mechanical strength, microstructure, phase composition and expansion were examined. Results showed that the HCA in connection with GP gave a good alkali activated binding materials for some special applications. In addition to that, the GP + HCA mixtures could be prepared with neither Portland cement nor any additional activator using exclusively waste materials. This is important for the perspective of reducing the CO2 emission. Presented materials were prepared. This is the first work which presents the usage of GP as an alkali activator.

In this paper, the analysis of the local exergy costs of a cullet glass heated by microwaves in a cubical cavity activated by a susceptor is presented. The analysis is based on a previously validated 3-D electromagnetic model, but goes further by applying the concepts of local exergy efficiency and local unit exergy consumption, what enables a local analysis (in time and space) of the process efficiency. Furthermore, local exergy cost quantifies in detail the path of the exergy cost formation during microwave heating, which is determined by the local irreversibilities taking place in this transient process. Four different susceptor positions have been also compared, in order to find out not only which one is the most efficient but also to justify in detail this result by the time and space evolution of efficiency, unit exergy consumption (both external microwave power and conduction contributions) and unit exergy cost. The best conclusion of the paper is that the local exergy cost approach can contribute to the design of more efficient energy conversion systems, as it could be noted in its application to a complex process like this 3-D example of microwave cullet heating.

This study investigates the potential of the use of recycled glass powder in foam concrete as a sustainable solution for future construction. The effects of cement and recycled glass powder contents, water to cement ratio and volume of foam on the plastic density, dry density, and compressive strength of foam concrete were investigated. The compressive strength of foam concrete without and with recycled glass powder increased with the increase in the plastic density and dry density of foam concrete. The direct replacement of cement with recycled glass powder (20% by mass) increased the compressive strength of foam concrete. Refereed/Peer-reviewed

The present work investigated the microwave (MW) zeolitization of waste glass cullet using landfill leachate as a new potential solvent. The leachate-based zeolites were synthesized in two sets, one with metal precipitation and filtration (F-zeolite) and the second one with unfiltered metal precipitates (UF-zeolite). These two cases were compared with reference zeolites produced using deionized water (D-zeolite) in terms of their characteristics. Different characterization techniques were used including XRD, EDX, SEM, FTIR, TGA, and cation exchange capacity (CEC). Presence of cations other than Na+ in leachate elevated the generation of hot spot zones and synthesized highly crystalline zeolites using unfiltered leachate. Substantial reduction in Na+ concentration due to the solid filtration also favored the production of a roughly single-phase hydroxysodalite (HS) and suppressed zeolite NaP1 formation using filtered leachate. Deionized water also produced a small fraction of zeolite NaP1 due to the lower Na+ content compared to unfiltered leachate. Zeolite synthesized using unfiltered leachate was also superior in cation exchange and water holding capacities due to its least Si/Al ratio as confirmed by EDX, TGA, and CEC results. The results from this study contribute to shed light on the efficiency of leachate application for large-scale zeolite synthesis in future prospect.

The present work studied the conversion of waste glass (WG) cullet into zeolite using microwave (MW) radiation technique. The temperature and power of radiation were monitored through constant temperature (MWCT) and constant power (MWCP) modes. Indirect fusion synthesis (IFS) and direct hydrothermal synthesis (DHS) conversion methods were studied and the zeolites synthesized by these methods were compared in terms of their characteristics using various techniques including XRD, EDX, SEM, FTIR, TGA, and cation exchange capacity (CEC). IFS was an efficacious synthesis technique and produced zeolites with a much higher crystal growth efficiency compared with those synthesized by DHS method. The IFS method was better than the DHS method as it eliminated the inhibitive effect of soluble aluminates on Si release. The IFS zeolites also provided lower Si/Al ratio and consequently higher cation exchange and water holding capacities compared to DHS zeolites, as validated by EDX, TGA, and CEC results. In addition, high pressure and high-temperature environment deteriorated the zeolite structure and diminished the crystal growth performance. The application of cooling air jet (CAJ) through MWCP mode provided efficient monitoring of temperature overshoot and excessive pressure generation by cooling the excessive generated hot spot zones. Therefore, the CAJ application improved the crystal growth in IFS method as higher radiation powers were applied.

The use of waste glasses as aggregates in cementitious materials provides a viable recycling option to alleviate the burden on landfills in Hong Kong. More interestingly, the light-transmitting properties of glass are beneficial to augment the TiO2-mediated photocatalytic activity. This study attempted to take full advantage of glass aggregate (GA) by attaching nano TiO2 particles on its surface. NaOH etching was employed to pre-treat the surface of GA in order to increase its surface area before TiO2 particles were attached. The experimental results showed that the treatment of NaOH etching effectively induced cracks and pores on the initially smooth surface of GA. As a result, a higher amount of nano TiO2 particles (0.0434 g per 50 g of GA) were attached/absorbed on the surface of the treated GA compared to the untreated analogue (0.0224 g per 50 g of GA) when immersed in 10 g L−1 TiO2 solutions. More importantly, the higher TiO2 absorption ability of the treated GA translated into a higher photocatalytic NOx removal activity. Compared with the untreated GA-TiO2 composites, the NaOH etched GA-TiO2 composites (immersed in 1 g L−1 TiO2 solutions) experienced an approximately 60% increase in the photocatalytic NOx removal efficiency. The overall findings revealed that compared with the sand-TiO2 composites, the NaOH etching treated GA-TiO2 composites not only garnered the beneficial effect from the light-transmitting of glass but also had the beneficial etching effect of NaOH treatment. Therefore, the developed NaOH etched GA-TiO2 composites hold great potential for applications in cementitious photocatalytic materials.

From a sustainability point of view, the disposal of non-recyclable glasses like Pyrex, tempered glass, and borosilicate glass gradually become an environmental issue because non-recyclable glass is a non-biodegradable material. To obtain high glass recycling ratios without remelting, many researchers have used not only crushed glass as an alternative to both fine and coarse aggregate in concrete, but also used ground glass powder as a pozzolanic material to enhance the formation of calcium silicate hydroxide (C S H). In general, concrete is known as a good fast neutron moderator due to its high hydrogen content but does not contain boron compound used for absorption of a thermal neutron. In this work, borosilicate glass was, therefore, used as a form of mineral additive and fine aggregate to produce neutron shielding mortar in this work. Furthermore, it was investigated whether the use of borosilicate glass powder can mitigate the expansion caused by alkali-silica reaction (ASR) between alkali in cement and the reactive silica in borosilicate glass aggregate or not. Test results indicate that 20% borosilicate glass powder replacing cement was able to control the ASR expansion. When borosilicate glass powder and aggregates were used simultaneously, the compressive strength of the mortar mixture increased. Moreover, the combined use of borosilicate glass powder and aggregates could shield 86% additional thermal neutron, leading to the possibility of using borosilicate glass for neutron shielding purposes.

Thermoplastic resin systems have long been discussed for use in large-scale composite parts but have yet to be exploited by the energy industry. The use of these resins versus their thermosetting counterparts can potentially introduce cost savings due to non-heated tooling, shorter manufacturing cycle times, and recovery of raw materials from the retired part. Because composite parts have high embedded energy, recovery of their constituent materials can provide substantial economic benefit. This study determines the feasibility of recycling composite wind turbine blade components that are fabricated with glass fiber reinforced Elium® thermoplastic resin. Several experiments are conducted to tabulate important material properties that are relevant to recycling, including thermal degradation, grinding, and dissolution of the polymer matrix to recover the constituent materials. Dissolution, which is a process unique to thermoplastic matrices, allows recovery of both the polymer matrix and full-length glass fibers, which maintain their stiffness (190 N/(mm g)) and strength (160 N/g) through the recovery process. Injection molded regrind material is stiffer (12 GPa compared to 10 GPa) and stronger (150 MPa compared to 84 MPa) than virgin material that had shorter fibers. An economic analysis of the technical data shows that recycling thermoplastic–glass fiber composites via dissolution into their constituent parts is commercially feasible under certain conditions. This analysis concludes that 50% of the glass fiber must be recovered and resold for a price of $0.28/kg. Additionally, 90% of the resin must be recovered and resold at a price of $2.50/kg.

A rapid zeolite synthesis procedure was investigated using pulverized waste glass cullet via microwave radiation and compared with zeolites synthesized using convection heating. It was observed that constant temperature microwave synthesis method made zeolites more efficiently under superheating conditions with a maximum relative crystallinity of 60%. The maximum relative crystallinity of the synthesized zeolites was found to be similar when convection heating and constant temperature controlled microwave synthesis was used; however, the latter technique offerred a factor of 140 reduction in synthesis time. This rapid synthesis process is attractive to the industrial application due to its high-energy efficiency.

Glass recycling can help reduce resource consumption, waste, energy use, and air and water pollution. Recycled glass products are figuring more prominently in global environmental policy trends. However, glass recycling product design is confronted with uncertainty of market demands. Manufacturers of various glass recycling product types such as glass art, glassware, and building materials face challenges of better understanding the needs of users and connecting user demand to product design prototypes, resulting in product design and user barriers. This study aimed to define a user experience-based product design approach from a people-oriented perspective. The proposed smart production approach to empowering industry 4.0 in the circular economy of the glass recycling industry explores product decision-making information systems and data-driven innovation. To understand user preferences for products, this study focused on key product factors and crucial user characteristics. Decision-making information systems were employed to identify the user experience for product and service design to provide useful information for smart production. This study was conducted in cooperation with a leading glass recycling company in Taiwan to enhance recycling incentives and empower industry 4.0 in the circular economy.

The present investigation focuses on the production of synthetic wollastonitic glass ceramics (WGCs) through vitrification of medical wastes incinerator fly ash (MFA) with soda lime recycled glass (SLRG) at 1300 °C, followed by re-crystallization in the range of 950 °C. The sintering process was carried out at the final temperature, previously determined by differential thermal analysis (DTA). The raw materials as well as the produced WGCs were characterized by chemical mineralogical and microstructural analyses. Their leaching behaviour was evaluated using the EN 12457-2 compliance leaching test. Re-crystallization led to the development of glass ceramics with two major crystalline phases: monoclinic wollastonite (b-CaSiO3) and gehlenite (Ca2Al2SiO7). The compressive and bending strength values varied from 190 to 194 MPa and 79–82 MPa, respectively. Although MFA exhibited high metals leaching values, indicating a hazardous waste, no trace elements were detected in the leachates of the WGCs.

Glass fiber reinforced polymer (GFRP) panels from retired wind turbines were recycled into discrete structural elements in mortar. Based on 7-day testing, out of Powder, Small, Medium, and Large fiber size groups, the Large group was identified as the optimum size due to the highest modulus of rupture (MR) and toughness index (TI) while maintaining comparable compressive strength (f’c) relative to control. Implementing the Large group at 1, 3, and 5% replacement of sand resulted in 5, 25 and 35% increases in 90-day MR with significant increases in TI and minimal reductions in f’c and no expansion due to alkali-silica reaction.

Disposal of consumer waste is a major challenge in urban areas around the world. In the field of building materials, it has long been recognized that many types of wastes can be used instead of raw materials. In addition, production of binders such as Portland cement is a CO2 intensive process. However, for widespread use of wastes in construction, it is important that the properties of resulting building materials are satisfactory. For concrete, the most important are the fresh, hardened and durability properties. A promising waste material that can be utilized to create sustainable concrete composites is waste recycled glass. In this paper, literature dealing with use of waste recycled glass as partial replacement of either cement or aggregate in concrete is systematically reviewed. The focus of this review is the influence of recycled waste glass on the engineering properties of concrete. Main advantages and drawbacks of using recycled waste glass are discussed. The aim of this review is to identify major research needs in the field that will help bring this class of materials closer to worldwide practical use. Given that concrete is the most used man-made material in the world, such development would significantly reduce the need for landfilling of waste recycled glass that is unsuitable for reuse in glass production.

The current study deals with the development of low-temperature stoneware tiles with boron-rich waste glass as sintering promotor in a modified triaxial ceramic body. The obtained results are part of a larger project financed by the Italian region of Emilia Romagna and aiming at developing novel formulations for sustainable ceramic products classified as porcelain stoneware. We successfully obtained highly vitrified ceramic tiles (BIa class) at a firing temperature almost 140 °C lower than that normally applied for this product by modifying a traditional triaxial composition and including waste glass. The ecological sustainability was thus improved by lower emissions and substitution of natural raw materials with secondary ones. Pilot scale trials confirmed full adaptability to existing powder processing routes. The microstructure and the temperature-induced phase evolution were analyzed by scanning electron microscopy (SEM) and quantitative phase analyses using X-ray powder diffraction (XRPD) and the Rietveld method. It will be shown that the triaxial body minerals are highly reactive in the boron-rich viscous melt leading to eutectic melting and recrystallization. The high reactivity renders this particular ceramic system flexible in terms of liquid phase composition and post-firing crystal assemblages and is therefore suitable as a base system for design of sustainable ceramic products.

This study investigated the viability of using calcium carbide residue (CCR) as an alkaline activator and recycled glass powder (RGP) as a precursor to improve properties of clay soils. The chemical composition of soil, RGP and CCR were determined by XRF. A compressive strength test was run on the specimens to investigate their mechanical behavior. The effect of different factors such as the CCR content, RGP content, initial synthesis temperature and curing time was investigated. SEM/EDX analysis confirmed the formation of a geopolymeric gel. The results show that both CCR and RGP materials can be used to stabilize clay soil.

This report details a cost-effective new process for transforming mixed waste glass into high-value building materials without remelting. Worldwide, waste glass is a growing burden and new options are urgently needed for the large volumes of speciality, mixed, broken and contaminated glass that cannot currently be recycled. Conventional glass recycling technologies are limited by the need to separate waste glass into different glass types and the extreme sensitivity of the remelting process to any contamination. In this study, we demonstrated that mixed broken glass could be used as primary input in the production of polymeric glass composites. The composites’ mechanical properties, utility, aesthetic appeal and expected market value were comparable to natural and engineered stone products, widely used as kitchen and bathroom benchtops and floor and wall tiles. Waste glass powder with an average particle size smaller than 108 μm was ground then mixed with resin as a binder before the mixture was hot-pressed under pressure. Various ratios of waste glass to resin binder, as well as the effect of a coupling agent and reinforcing mesh were tested. The optimum PGC achieved a flexural strength of 48 MPa, water absorption below 0.002%, a density of 2.113 kg/m3 and compressive strength of 101 MPa with minimum scratch, wear and UV degradation behaviour. Its excellence in the mechanical value stand in parallel with engineering stone but, with cheaper and efficient process. Additionally, this new recycling process embodies an important unique alternative to the remelting of waste glass with the potential to deliver economic and environmental benefits wherever waste glass is stockpiled.

In order to improve the understanding of glass production and provenance, we present trace element and Sr, Nd and B isotope ratio data for 15 samples of raw natron glass from a single tank furnace in Apollonia (6th-7th century CE) and eight glass samples from two tank furnaces in Bet Eli'ezer (8th century CE) in Israel. This data provides information about the geochemical homogeneity within a single batch of raw glass and about the differences and/or similarities between different tank furnaces on a single site. Four glasses from a secondary workshop at Tell el-Ashmunein, Egypt (8th-9th century CE) are analysed for comparative purposes.All raw glass samples have uniform trace element patterns and ratios. Because of poor mixing of the glass batch before and during firing, absolute concentrations however can vary significantly within a single tank furnace. The concentrations of trace elements commonly associated with (de)colouring are very low and can be attributed to background concentrations in the sand raw materials. This indicates that there was no obvious recycling of glass culler at this stage of the production process and that the tank furnace glass is primary glass in the true sense of the word. The isotopic compositions of Sr, Nd and B in the tank furnace glasses are relatively homogeneous. This confirms their potential as provenance indicators. The isotopic composition of Sr in tank furnace glass from Apollonia and Bet Eli'ezer indicates that the lime was derived from seashell, suggesting the glass was produced from beach sand. Glass from Tell el-Ashmunein contains Sr with lower Sr-87/Sr-86 ratios, pointing to the use of limestone as the source of lime. All primary glasses from Israel analysed have Nd isotopic compositions typical for an Eastern Mediterranean origin. delta B-11 indicates that natron used in the tank furnaces in Apollonia and Bet Eli'ezer was most likely imported from Egypt

Previous studies have well demonstrated that recycled glass (RG) can be incorporated into cementitious materials to replace 100% river sand as fine aggregates. However, this replacement was found to incur adverse effects on the mechanical properties of the cement mortar. In this study, CO2 curing was employed to ameliorate these drawbacks. The effect of CO2 curing on both of the mechanical properties and microstructure of the RG incorporated cement mortar was studied by a series of laboratory tests. The results showed that replacement of river sand by 100% RG led to a 37% decrease in compressive strength and a 32% reduction in flexural strength of the mortar samples under conventional curing. Whereas, CO2 curing of these samples significantly enhanced both the compressive and flexural strength, with a more pronounced improvement on the former. Such improvements were further reflected by a decrease in both the water absorption and porosity, and by an enhancement of the microstructure. This is attributed to the fact that compared with the mortar samples prepared with 100% river sand, those prepared with 100% RG had a more porous structure due to the smooth surface of RG and thus a poor bonding between the RG and the cement paste. However, such a porous structure encouraged CO2 gas to penetrate and diffuse more easily into the cementitious matrix, resulting in a higher degree of CO2 curing.

The use of various wastes in the manufacture of different ceramic products has proved to be beneficial from both economic and environmental points of view. In the present paper, the simultaneous reuse of ceramic sludge waste (from 0% to 6.2%) and cullet (from 0% to 10%) in the production of vitrified clay pipes has been investigated. Samples were pressed at 15 MPa, dried and subsequently fired at three different temperatures (1050, 1150 and 1250 °C) and soaking times (1, 2 and 3 h). A two-level factorial design was applied to study the effect of the various parameters on the properties of fired bodies. It was concluded that an economic recipe can be prepared involving the use of 6.2% sludge (dry basis) and 5% cullet with the balance clay + grog followed by firing the dried body at 1050 °C for one hour only. The produced fired specimens yielded bending strength exceeding the minimum requirement for any size of soil embedded pipes and for 8″ and larger concrete cradled pipes. The suggested composition makes use of an environmentally polluting waste (sludge) and broken glass waste (cullet) and involves firing for one single hour at a temperature about 200 °C lower than commonly used.

The process of foaming glass is very dependent on the chemical composition of the glass. In this study we used a foaming-agent/oxidizing-agent couple and a crystallization inhibitor to foam cullets of flat, container and CRT-panel glass. Foamed glass with a density of 110–120 kg m –3, a thermal conductivity of 50–52 mW m –1 K –1 and a homogeneous pore structure was obtained from a mixture of panel glass, 0.33 wt% carbon and 4.45 wt% Fe 2O 3. We also showed that it is possible to fabricate foamed glass with the same density or pore structure as mentioned above by adding up to 50 wt% container cullet or 70 wt% flat glass to the mixture. In the foamed samples with a low content of panel glass, crystals form, resulting in an increased open porosity, density and inhomogeneous pore structure. The crystallization can, however, be inhibited by adding calcium phosphate, so enabling the preparation of high-quality foamed glass from flat glass or flat/container-glass mixture. The pore gas is predominantly CO 2 and the pressure inside the pores is 0.36–0.47 bar. The reduced effect of the composition on the foaming process suggests that there is a great potential for stabilizing the production of foamed glass and ensuring the product's quality.

Hazardous residues from ferronickel production and glass cullet were mixed and vitrified. After low-cost heat-treatment the obtained glass was transformed in a fine-crystalline glass-ceramic. The evolution of structure during the crystallization cycle is studied by XRD and SEM-EDS. Finally, the morphology of final glass-ceramic was elucidated by TEM and FESEM. Due to the elevate amounts of iron and magnesium oxides and the presence of ∼2 wt % chromium oxides in the composition, the crystallization process is peculiar and the final structure of glass-ceramic is complex. Some preliminary Fe-Mg-Cr spinel crystals with size of few microns precipitate during the melt cooling. Then, these crystals act as centres for the growth of a pyroxene phase; thus, 15–20 vol% of the glass-ceramic structure is formed. The major amorphous phase, where Cr2O3 concentration becomes negligible, is characterized with a high immiscibility trend, leading to the formation of Fe-rich droplets with size of 50–70 nm. Subsequently, these droplets are transformed into nano magnetite crystals, which provoke crystallisation of the main pyroxene phase. This “second” new pyroxene phase differs by the one, already formed on the preliminary Fe-Mg-Cr spinel, and is composed by mono-crystals with size of 150–200 nm.

This research focuses on the potential use of fly ash (WAf) from a Chinese pulverized-coal combustion (PCC) power plant for manufacturing foam glass. The influences of fly ash properties, fly ash/recycled glass proportion in the raw materials, addition of fluxing and foaming agent, firing temperature, and residence time at the peak temperature on the final properties (apparent density, compressing strength and leachable potential of major and trace elements) of the foam specimens are investigated. The optimal foaming products were obtained consuming up to 33.3–43.3% fly ash, adding 9–11% Na2CO3 fluxing agent and 0.5% SiC foaming agent, firing at 865–915 °C during 15 min residence time at the peak temperature. The obtained fly ash-based product revealed comparable compressive strength but slightly higher densities than commercial foam glass, with low CO2 emissions and low leachable potential for environmentally relevant trace elements within the limits for inert/no-hazardous material established by the European Council Decision 2003/33/EC for land waste disposal. The large porosity of the foam glass indicates a high potential of thermal and acoustic insulation. The foaming behavior and the final properties the foam glass are strongly influenced by properties of fly ash (mainly fluxing temperature and organic C content), fly ash/recycled glass proportion in the raw materials, addition of Na2CO3 fluxing agent and SiC foaming agent, firing temperature, and residence time at the peak temperature. The low C content and high refractory character of WAf give rise to poor foaming of the specimens when only fly ash and Na2CO3 mixtures are used. The consumption of relatively high proportions of recycled glass and SiC is essential to produce foaming.

Many waste ceramic materials and glasses (CerG) such as glass, concrete, pottery, porcelain, brick, and tiles are landfilled because they have been recognized to be less conducive to recycling. In this study, to enhance the recyclability of ceramic materials and glasses, a linear model to minimize natural resource consumption of CerG materials production is proposed. The model focuses on elementally based contents of substances in the CerG materials. The model demonstrates a case for major industrial ceramic materials consisting of eleven oxides: Al2O3, B2O3, CaO, Fe2O3, K2O, MgO, MnO, Na2O, P2O5, SiO2, and TiO2 in Japan. In addition to the ceramic materials and glasses within the eleven oxide systems, application of the same natural resources to by-products or waste materials such as ironmaking slag and sewage sludge molten ash, are included in this analysis. In the proposed model, for minimizing natural resource consumption to produce the target CerG, linear programming was employed to assess waste generation and new production of CerG, subject to supply and demand balance and elemental tolerance ranges of chemical compositions in CerG materials. Two discrepancies were found between the proposed model and the characteristics of materials or usages of materials. Therefore, in the case study, several kinds of CerG materials were not applicable in the analysis. Even though costs for recovered materials restrict economic feasibility for recycling waste CerG, economic aspects were not taken into consideration in the analysis. In addition, impurity contamination during recovery processes restricts recycling of CerG. If those two factors (which may restrict the current recycling systems) were ignored, around two-thirds of the current natural resource consumption for CerG could be reduced by promoting recycling in the case of Japan. Further, new recyclable paths could be found by those analyses such as ironmaking slag for flat glass, glass bottles, and glass wool; and sewage sludge molten slag for tiles.

This research investigated the feasibility of using a geopolymer based on recycled glass powder (RGP) to improve the mechanical behavior of clay soils. The chemical elements of soil and RGP were determined by XRF. Unconfined compressive strength (UCS) testing was used to investigate the mechanical behavior of specimens. The effects of different parameters, such as the RGP content, molar concentrations, curing time and temperature, were investigated. The results revealed that the UCS and (ef) of specimens that were stabilized using a geopolymer were increased in comparison to the unstabilized specimens. SEM-EDX was analyzed to investigate the microstructure of stabilized specimens.

The ever increasing demand for high-quality river sand in construction, which poses economic and environmental concerns, highlights the necessity for finding suitable alternatives. Waste glass has a very low impact tolerance, which makes it very easy to grind and use as a fine aggregate in the construction of lightweight building elements. In this study, glass fines are used as a replacement for fine sand in manufacturing geopolymer foams. The thermal and mechanical properties of the two systems with different densities are investigated and compared with a control sample of geopolymer foam with no aggregates. The geopolymer paste with sand aggregates has a density that was approximately 100 kg/m3 higher than the paste with glass aggregates. The heavier samples with sand aggregates required a higher degree of foaming to drop the density to a similar range, which negatively affects their strength. For a density of 1000 kg/m3, the geopolymer foams with glass aggregates are 25% stronger than the foams with sand aggregates. The strength improves further by 31% and 77% as the density drops down to 800 kg/m3 and 600 kg/m3, respectively. The shape of the bubbles in geopolymer foams with glass aggregates is more regular with less interconnectivity between pores, especially at lower densities. This pore characteristic enhances the insulation capacity of lightweight foams with glass aggregates where thermal conductivity of 0.15 W/mK was achieved in the sample with 600 kg/m3 density.

Partition wall blocks produced by using recycled concrete as aggregates may be exposed to fire conditions in real applications. It is of great significance to keep the thermal conductivity of the block as low as possible to minimize damages due to the outbreak of a fire. To do so, alternative and/or additional materials can be used in the preparation of the blocks, which can reduce the heat transfer rate with little degradation of strength. In this study, three kinds of waste materials derived from construction and demolition (C&D) waste were respectively used to add or replace fine aggregates by volume or weight, including polypropylene fiber (PP fiber), recycled glass (RG) and recycled polystyrene (RP) in preparing the partition blocks. The compressive strength, water absorption, density, thermal conductivity, porosity of the blocks before and after exposure to elevated temperatures of 300 °C, 500°Cand 800 °C were examined. The results indicated that at room temperature, the incorporation of PP fibers had negligible influence on the physical properties of the blocks with little reduction of compressive strength, while the replacement of fine aggregate by RP resulted in significant reduction in compressive strength as well as thermal conductivity. The use of RG as a fine aggregate could reduce the thermal conductivity without significant effects on the compressive strength of the block samples. Although the exposure to elevated temperatures brought about reduction in thermal conductivity, the increase in porosity led to a large reduction in compressive strength of the blocks prepared with RP. The most significant finding of the study was that using 100% RG as fine aggregate was beneficial to conservation of compressive strength especially after exposure to 800 °C due to the re-solidification of the melted RG upon cooling, which led to a better thermal insulation property of the blocks. A further study on the influence of RG on compressive strength based on the mortar blocks prepared with glass cullet as fine aggregates convincingly proved the improved fire resistance of using 100% RG especially after 800 °C. The use of RG for partition blocks production has significant advantages in terms of sustainability and fire resistance.

The borosilicate glass was recycled from high pressure sodium lamp glass (HPSg) and investigated as a starting material for radiation shielding glass. Bi2O3 was expected to improve radiation shielding properties of the glass samples. Mass attenuation coefficients, effective atomic number (Zeff) and effective electron density (Ne) of the glass samples ((80 – x)HPSg – (20)Na2O – (x)Bi2O3 (x = 0, 1, 2, 3, 4 and 5 mol%) were determined at different photon energies. The energy absorption buildup factor (EABF) and fast neutron removal cross sections were also calculated for the given materials. The results clearly revealed that mass attenuation coefficient and other parameters depends on concentration of Bi2O3 and addition of Bi2O3 significantly increased shielding capability of glass samples against gamma rays as well as fast neutrons. The results of Zeff and Ne confirmed the ability of shielding of the glass samples with Bi2O3 as well. Physical properties of glass samples were also investigated in the present work. The obtained ultrasonic velocities and Young's modulus of the glass samples led us to a conclusion that the network structures of the glass are loss of compact structures due to creation of NBOs when adding the Bi2O3. The FTIR measurements confirmed NBOs forming in the network structures of the glass samples with increase of Bi2O3 contents. The reported structural and radiation attenuation properties of recycled glass with Bi2O3 should be important in radiation shielding applications which requires high strength of structures at the same time.

The main goal of the work was to evaluate the vitrification process of asbestos-cement waste (ACW). A mixture of 50 wt% ACW and 50 wt% glass cullet was melted in an electric furnace at 1400 °C for 90 min and then cast into a steel mold. The vitrified product was subjected to annealing. Optical microscopy, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) were used to evaluate the effects of the vitrification. The chemical constitution of the material before and after the vitrification process was also analyzed. It was found that the vitrified product has an amorphous structure in which the components of asbestos-cement waste are incorporated. MIR spectroscopy showed that the absorption bands of chrysotile completely disappeared after the vitrification process. The results of the spectroscopic studies were confirmed by X-ray studies - no diffraction reflections from the chrysotile crystallographic planes were observed. As a result of the treatment, the fibrous asbestos construction, the main cause of its pathogenic properties, completely disappeared. The vitrified material was characterized by higher resistance to ion leaching in an aquatic environment than ACW and a smaller volume of nearly 72% in relation to the apparent volume of the substrates. The research has confirmed the high effectiveness of vitrification in neutralizing hazardous waste containing asbestos and the FT-IR spectroscopy was found to be useful to identify asbestos varieties and visualizing changes caused by the vitrification process. The work also presents the current situation regarding the utilization of asbestos-containing products.

Green roofs are a key component to building sustainable cities because of their multiple environmental benefits, but without the proper level of care, the leachate from green roofs might contain pollutants and become a new nonpoint pollution source in urban areas. Because its leachate quality is affected by the substrates and plants used, the objective of this study is to evaluate the effects of the substrates and plants with the aim of improving green roof applications. This study tested 3 materials – normal cultivated (C) substrate, commercial green roof (L) substrate, and mixed C and recycled glass (R) substrate – with a focus on using recycled glass materials in the green roof system. Recycled glass is a lightweight and porous material that improves pollutant absorption and water quality purification. Three different types of plants were tested: a sedum, a fern, and a shrub. Therefore, this study evaluated 9 combinations, each with 3 replicates. The differences in the substrates exerted significant effects on the chemical oxygen demand (COD) and phosphorous (P) concentrations. The nitrogen (N) concentrations were affected by differences in both the substrates and the plants. The changes in the observed water quality with time implied that compact substrates and mature plants reduced pollutant concentrations, except for N concentrations, in the outflow. The L substrate contained high levels of nutrients, and the plants grew better in this substrate than in the other two substrates; however, the L substrate also produced higher pollution concentrations. The R substrate, with recycled glass, performed well in the neutralization of acid rain but did not significantly reduce the levels of other pollutants. To enhance the purification ability of the recycled glass, the mixing ratio between the recycled glass and organic substances and the placement in the substrate are important factors.

Waste cadmium sulfide (CdS) film electrodes, originally deposited onto glass/fluorine doped tin oxide (glass/FTO) substrates, were used to prepare recycled CdS film electrodes. The waste glass/FTO/CdS were processed in acidic media to recover the glass/FTO substrates, the Cd2+ ions (in the acidic solutions) and the gaseous H2S (recaptured in basic media). All components of the waste electrodes were thus recovered. The recovered glass/FTO and the Cd2+ ions were then reused to produce new recycled glass/FTO/CdS electrodes by chemical bath deposition. The produced films were then characterized by X-ray diffractometry, scanning electron microscopy, electronic absorption spectroscopy and other techniques. The Cd2+ ions were recovered with efficiency higher than 90% from the waste films, as observed from atomic absorption spectrometry. The recycled films were assessed in photo-electrochemical conversion of light to electricity, and exhibited comparable efficiency to those freshly prepared from authentic starting materials and other literature values. Photoelectrochemical characteristics for the recovered films were further enhanced by avoiding stirring of the chemical deposition bath during preparation. The results manifest the feasibility of recycling CdS electrodes and enhancing their photo-electrochemical characteristics by simple low cost methods. Both environmental protection and economic goals can thus be potentially achieved.