Potential Recycling Research Articles

Synthesis of C,N,S-tridoped TiO<sub>2</sub> distribute onto silicone for photocatalytic on degradation of tetracycline under visible light irradiation

Using carbon, nitrogen, and sulfur sourced from thiourea to co-doped TiO2 (C,N,S-TiO2), was prepared via hydrothermal method using precursors of titanyl sulfate TiOSO4, obtained by decomposition of ilmenite ore in Binh Dinh. The material used to make the substrate is glass and distributed onto it is silicone and photocatalytic. The structure and properties of materials system were investigated by modern physicochemical analysis methods including scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectra, diffuse reflection spectroscopy UV-Vis, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX) and nitrogen isothermal adsorption. The photocatalytic ability of materials system after being carried by silicone is demonstrated by decomposing tetracycline (10 mg/L) in aqueous solution with the yield more than 88% efficiency after 6 hours under visible light irradiation. The optimum dose of the photocatalyst was 0.6 g/L under visible light irradiation. The results indicated that C, N, S co-doped TiO2 demonstrated the highest photocatalytic efficiency and a perspective recyclable potential when it is distributed onto silicone.

Flotation separation of acrylonitrile-butadienestyrene (ABS) and high impact polystyrene (HIPS) from waste electrical and electronic equipment (WEEE) by potassium permanganate surface modification

The wasted acrylonitrile–butadienestyrene (ABS) and high impact polystyrene (HIPS) have a great potential for recycling. However, it is difficult to recycle them due to the absence of an effective separation method. Permanganate oxidation is a kind of environmental protection process and plays an important role in green chemistry. In this study, the polymer surface modification by potassium permanganate was utilized to separate ABS and HIPS from waste electrical and electronic equipment (WEEE) by flotation. Attenuated total internal reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) results showed that potassium permanganate can oxidize butadiene and nitrile groups in ABS to form oxygen-containing hydrophilic groups. Butadiene in HIPS can also be oxidized to form oxygen-containing hydrophilic groups, but the increase is less than that of ABS. Scanning electron microscope (SEM) results show that the surface roughness of ABS is improved, but HIPS has no obvious change, which indicates that the surface wettability of ABS can be further improved with the improved surface roughness. The contact angle test results show that the contact angle decrease of ABS after surface modification is significantly higher than that of HIPS. The results showed that the optimum modification conditions are as follows: the concentration of potassium permanganate solution is 50 mM/L, modification temperature of 60 °C, and the modification time 30 min. The recovery and purity of ABS are 97.64% and 95.41%, respectively, and the recovery and purity of HIPS are 95.40% and 97.64%, respectively. This research provides a technical support for the high-value recycling of WEEE waste plastic.

Recycling of tungsten: Current share, economic limitations, technologies and future potential

Recycling is an essential part of the global tungsten flow. A wide variety of recycling technologies for tungsten exists today. Processes are tailored to deal with different scrap types and to produce well-defined recycling products. The paper presents the current share of recycling in the global tungsten flow and elaborates on the economy of recycling. The available recycling technologies and their industrial relevance is summarized. Based on the tungsten end-use pattern and the associated tungsten products, the future potential of tungsten recycling is discussed.

Recycling potential in building energy renovation: A prospective study of the Dutch residential building stock up to 2050

Building energy and construction and demolition waste (CDW) are highly relevant but intertwined issues for the transition towards a carbon-neutral and circular built environment. Ongoing energy renovation uses an increasing number of emerging materials that pose a challenge for recycling. As a response, a novel technological system has been proposed to recycle CDW (including insulation mineral wool and lightweight concrete) for the manufacture of prefabricated concrete elements (PCEs) for use as façades for new (PCE-new) and retrofitting existing (PCE-refurbs) buildings. To explore how this novel system can improve recycling potential as part of building energy renovation efforts, the Dutch residential building stock was selected as a case study. Using a dynamic material flow analysis, we explore the supply-demand balance of secondary raw materials made from CDW (including normal-weight and lightweight concrete, glass, insulation mineral wool, and steel) and the secondary raw materials required for manufacturing PCEs in building energy renovation for the period 2015–2050. Our findings show that with advanced recycling technology, the secondary raw materials recovered from normal-weight concrete waste, glass waste, insulation mineral wool waste, and steel scrap will be more than sufficient to support the manufacturing of PCE-new walls, implying the possibility of closed-loop construction. However, for emerging materials such as lightweight concrete, the related waste will not be sufficient in the near future to meet the raw material demand for large-scale refurbishment with PCE-refurbs. Therefore, the Dutch case shows that the novel technology system offers a promising solution to CDW management problems in building energy renovation, but primary raw materials will still be needed for the increased use of emerging materials such as lightweight concrete.

Multifunctional magnesium oxychloride based composite with stable superhydrophobicity, self-luminescence and reusability

Magnesium oxychloride (MOC) based materials have attracted much concern because of the superior mechanical properties and environmental friendliness, however, the widespread application is limited by the poor water-resistance and the tedious function. Thus it is worthwhile devoting much effort to overcome the defects. Here, taking sandpaper as template and with the modification of fluorinated HPDMS and luminescent powder, an effective method is proposed to produce MOC based composite with superhydrophobicity, self-luminescence and reusability. The samples can keep superhydrophobic (SHP) after enduring mechanical and chemical treatments, and even the crushed sample is still superhydrophobic. Meanwhile, SHP modification is helpful for overcoming the poor water-resistance, because the main phases are protected by the hydrophobic layer. After excitation, the composite materials can emit green light, which will gradually decay with time. The superhydrophobicity makes the material endure to be used for buildings with self-cleaning and deicing ability. Moreover, the powders ground from waste samples exhibit superhydrophobicity, implying the potential recyclability of this material, which can be applied to SHP luminous coating for house decoration and traffic signs in darkness, and directional water transport as well.

Novel Method for the Isolation of Proteins and Small Target Molecules from Biological and Aqueous Media by Salt-Assisted Phase Transformation of Their PEGylated Recognition Counterparts.

An efficient and simple method for the application of PEGylated affinity ligands in precipitative isolation of protein target molecules (TMs) from a biological fluid such as blood serum or small target molecules from an aqueous medium is presented for the first time. This approach is based on the high binding specificity of PEGylated recognition molecules (PEG-RMs) to their TMs and the unique physicochemical properties of PEG that result in their salt-assisted phase transformation. Addition of PEG-RM to blood serum results in the formation of an RM-specific macromolecular complex (PEG-RM + TM → PEG-RM.TM) that undergoes facile salt-assisted phase transformation to a separable semisolid with ammonium sulfate. PEG-RM.TM is then dissociated into its components by pH reduction or an increase of ionic strength (PEG-RM.TM → PEG-RM + TM). PEG-RM is salted out to afford pure TM in solution. The same phenomenon is observed when RM or TM are small molecules. The general applicability of the method was validated by PEGylation of two proteins (protein A, sheep antihuman IgG) and a small molecule (salicylic acid) used as model RMs for the isolation of Igs, IgG, and serum albumin from blood serum. The isolated protein TMs were shown to be pure and aggregate-free by gel electrophoresis and dynamic light scattering (DLS). IgG isolated by this method was further characterized by peptide mass fingerprinting. PEGylated protein A was used to demonstrate the recyclability and scale-up potential of PEG-RM. IgG isolated by this method from blood serum of a hepatitis C-vaccinated individual was tested for its binding to sheep antihuman IgG by UV spectroscopy, and its bioactivity was ascertained by comparison of its enzyme-linked immunosorbent assay (ELISA) result to that of a blood sample from the same individual. Reciprocity of RM and TM was ascertained using PEGylated salicylic acid to obtain pure serum albumin, and PEGylated serum albumin was utilized for near-exclusive isolation of one drug from an aqueous equimolar mixture of three drugs (salicylic acid, 91%; capecitabine, 6%; and deferiprone, 3%). Advantages of this approach, including target specificity and general applicability and celerity, over other affinity methods for the isolation of proteins are discussed at a molecular level.

Current and potential recycling of exogenous organic matter as fertilizers and amendments in a French peri-urban territory

Animal breeding, industries and cities produce byproducts and wastes that can be recycled in agriculture as exogenous organic matters (EOMs), promoting soil carbon storage and nutrient recycling. Peri-urban areas show a strong potential for recycling urban EOMs in agriculture. This potential needs to be better quantified in regard to farmer fertilizer demand. We investigated this question in a peri-urban territory, namely, the Versailles plain, which is located near Paris, France. We coupled interviews with farmers and waste managers with regional datasets to identify accurate flows of organic matter and their associated nutrients. The EOM potential for C storage was assessed with the AMG soil carbon model. Potentials for P, K and (short-term) N fertilizer substitutions were based on fertilizer equivalent coefficients. Additionally, we assessed the potential additional mineral N release related to increased soil organic matter after repeated EOM applications. For social and technical reasons, local EOM recycling was unequal; it was high for manures and compost and low for sewage sludge. Inputs of efficient C into soils due to EOM recycling corresponded to 20% of the inputs from crop residues. Current EOM use met 44% and 50% of the crop P and K demands, respectively. The potential for N fertilizer substitution was very low but increased when considering the additional mineral N available after long-term EOM applications. EOM could reach higher potential, especially when considering the anaerobic digestion of biowaste and potential source-separation of human urine (up to the whole P and K demand and half of N demand).

Urban agriculture — A necessary pathway towards urban resilience and global sustainability?

The Covid-19 pandemic newly brings food resilience in cities to our attention and the need to question the desired degree of food self-sufficiency through urban agriculture. While these questions are by no means new and periodically entering the global research focus and policy discussions during periods of crises — the last time during the global financial crisis and resulting food price increases in 2008 — urban and peri-urban agriculture continue to be replaced by land-uses rendering higher market values (e.g. housing, transport, leisure). The loss of priority for urban agriculture in urban land-use planning is a global trend with only a few exceptions. We argue in this essay that this development has widely taken place due to three blind spots in urban planning. First, the limited consideration of social and ecological vulnerabilities and risk-related inequalities of urban inhabitants, food shortage among them, in the face of different scenarios of global change, including climate change or pandemic events such as Covid-19. Second, the disregard of the intensified negative environmental (and related social) externalities caused by distant agricultural production, as well as lacking consideration of nutrient re-cycling potentials in cities (e.g. from wastewater) to replace emission intensive mineral fertilizer use. Third, the lack of accounting for the multifunctionality of urban agriculture and the multiple benefits it provides beyond the provision of food, including social benefits and insurance values, for instance the maintenance of cultural heritage and agro-biodiversity. Along these lines, we argue that existing and new knowledge about urban risks and vulnerabilities, the spatially explicit urban metabolism (e.g. energy, water, nutrients), as well as ecosystem services need to be stronger and jointly considered in land-use decision-making.

The Development of Efficient Contaminated Polymer Materials Shredding in Recycling Processes.

Recently, a dynamic increase in the number of polymer elements ending their life cycle has been observed. There are three main ways of dealing with polymer waste: reuse in an unchanged form, recycling (both material and energy), and disposal (mainly in the form of landfilling or incineration). The legislation of European countries promotes in particular two forms of waste management: reuse and recycling. Recycling processes are used to recover materials and energy especially from contaminated waste, which are structurally changed by other materials, friction, temperature, machine, process, etc. The recycling of polymers, especially of multi-plastic structural elements, requires the use of special technological installations and a series of preparatory operations, including crushing and separating. Due to the universality and necessity of materials processing in recycling engineering, in particular size reduction, the aim of this study is to organize and systematize knowledge about shredding in the recycling process of end-of-life polymeric materials. This could help properly design these processes in the context of sustainable development and circular economy. Firstly, an overview of the possibilities of end-of-life plastics management was made, and the meaning of shredding in the end-of-life pathways was described. Then, the development of comminution in recycling processes was presented, with special emphasis given to quasi-cutting as the dominant mode of comminution of polymeric materials. The phenomenon of quasi-cutting, as well as factors related to the material, the operation of the shredding machine, and the technological process affecting it were described. Research conducted on quasi-cutting as a phenomenon when cutting single material samples and quasi-cutting as a machine process was characterized. Then, issues regarding recycling potentials in the context of shredding were systematized. Considerations included the areas of material, technical, energy, human, and control potentials. Presented bases and models can be used to support the innovation of creative activities, i.e., environmentally friendly actions, that produce specific positive environmental results in the mechanical processing of recycled and reused materials. The literature survey indicates the need to explore the environmental aspect of the shredding process in recycling and connect the shredding process variables with environmental consequences. This will help to design and control the processes to get the lowest possible environmental burdens.

Flows of post-consumer plastic packaging in Germany: An MFA-aided case study

This study aims at defining the current state-of-affairs of the German post-consumer plastic packaging (PCPP) sector. By the use of the Material Flow Analysis (MFA) tool, a comprehensive investigation of the currently available PCPP waste collection and treatment system is conducted, which enables understanding the intrinsic inefficiencies of the waste value chain. The analysis utilises primary data (by conducting manual sorting activities) as well as secondary data (literature-based). Sorting has been performed taking into consideration the plastic packaging applications and material composition, polymer types, and moisture and dirt.Results show that the per capita generation of PCPP waste is 26.3 kg ± 3.0% in the year 2017 in Germany. The separate collection efficiency is 74.8% ± 2.9%, considering all separate collection systems (i.e. deposit system for PET bottles and Dual System). The study confirms that most of the material losses occur at the sorting stage mostly as a result of the complex packaging designs, where a combination of different materials is common practise. Overall, the net material recycling rate is 26.4% ± 1.3%, calculated on the basis of the net generated waste and excluding the potential recycling of the mixed polyolefin stream. If recycled material from mixed polyolefins is included, this figure increases to 37.8% ± 2.0%.The maximisation of the PCPP re-circulation potential requires collaborative policies addressing all the stakeholders in the value chain, starting from producers (product design), followed by the consumer (responsible and correct disposal), then the sorting facilities (by utilising state-of-the-art technologies and targeted sorting).

Synergistic effect for the degradation of tetracycline by rGO-Co3O4 assisted persulfate activation

In this work, reduced graphene oxide (rGO), Co3O4, and rGO–Co3O4 composites were successfully synthesized while their catalytic activity was evaluated regarding the degradation of tetracycline (TC) by persulfate (S2O82−) activation process in aqueous solutions. Surface morphologies, composition, and structure of the as produced materials were investigated with the aid of different techniques such as XRD, SEM, EDX, FT-IR, and BET analysis. The catalytic activity of rGO–Co3O4 composite was evaluated regarding TC degradation by K2S2O8 (PS). The results revealed that pure Co3O4, rGO, and rGO–Co3O4 were successfully synthesized. Co3O4 sample presented spinel structure, with an average diameter of 26.7 nm while C/O ratio in rGO sample was about 3.2. rGO–Co3O4 composite significantly enhanced the removal of TC with a typical efficiency of over twofold compared to sole Co3O4.About 96% of TC (5 mg/L) were decomposed by rGO–Co3O4/PS catalytic system after 60 min at room temperature. The catalytic performance of rGO–Co3O4/PS system was affected by pH of solutions, TC initial concentration, catalyst dosage, and PS concentration. The rGO–Co3O4/PS system degraded the most TC in aqueous solutions at the following condition: rGO = 200 mg/L, pH6, TC = 5 mg/L, and PS = 0.3 mM; it was shown to be a perspective recyclable potential with a TC removal efficiency of more than 84% after three reuse cycles.TC degradation process fitted the pseudo-first order kinetics the most (r2 = 0.98 for optimal condition), corresponding to a 0.023 min−1 rate constant. Both HO• and SO4•- radicals generated from the rGO–Co3O4/PS system were primarily species that degraded TC in solutions.

Preparation of magnetic nanomaterial for U (VI) uptake from the aqueous solution

Nanocomposite of magnetite-silica (Fe3O4@SiO2) was synthesized and walled with a shell of 5,7-dihydroxy-4-methylcoumarin (DHMC). The prepared dihydroxy-4-methylcoumarin magnetite-silica nanocomposite (DHMC-M-SNC) was used in the uranium uptake from the liquid phase in a batch system. The structure of DHMC-M-SNC was investigated by BET, XRD and FTIR analyses. DHMC-M-SNC appeared maximum sorption capacity reached 66.43 mg/g at 30 min and pH 5. The U (VI) sorption system onto DHMC-M-SNC was favorable at low temperature (Exothermic nature) and fitted well with Langmuir (R2 = 0.997) and pseudo-second-order models (R2 = 0.989). Also, recycling of DHMC-M-SNC shows a potential recycle up to 8 cycles. The results show that the prepared nanocomposite can be utilized as an operative sorbent in the U (VI) sorption from the liquid phase.

Remarkable enhancement of visible light driven photocatalytic performance of TiO2 by simultaneously doping with C, N, and S

• Eg of TiO 2 was reduced from 3.34 eV to 1.90 eV by doping TiO 2 with C,N,S elements. • Doping TiO 2 with C,N,S significantly improved the photocatalytic activity of TiO 2 . • Optimal photocatalyst dose and initial concentration of RhB were respectively 1.8 g/L and 20 mg/L. • Photocatalytic degradation of RhB followed the first-order kinetics. • C,N,S tri-doped TiO 2 catalyst was highly stable and effective to degrade RhB in solutions. TiO 2 modified with C, N and S were produced by hydrothermal treatment and sol–gel method using thiourea as the precursor. The characteristic of the materials were examined by means of XPS, XRD, UV–VIS, SEM, EDX, and FT-IR. The results showed that C, N and S were successfully doped into TiO 2 lattice, leading to a decline in recombination rate of electrons/holes, and a shift of absorption edge of TiO 2 to visible light region. The photocatalytic performance of as synthesized catalysts were evaluated via the degradation of rhodamine B under visible light irradiation. N,C,S-TiO 2 demonstrated the highest photocatalytic efficiency and a perspective recyclable potential. The optimal photocatalyst dose was 1.8 g/L, and the best RhB initial concentration was 20 mg/L. At the optimal conditions, almost 100% of RhB were removed after 1.5 h. The photodegradation of RhB followed the seudo first-order kinetics, with the maximum rate constant of 0.0410 min −1 .

Selective Chemical Upcycling of Mixed Plastics Guided by a Thermally Stable Organocatalyst

AbstractChemical recycling of plastic waste represents a greener alternative to landfill and incineration, and potentially offers a solution to the environmental consequences of increased plastic waste. Most plastics that are widely used today are designed for durability, hence currently available depolymerisation methods typically require harsh conditions and when applied to blended and mixed plastic feeds generate a mixture of products. Herein, we demonstrate that the energetic differences for the glycolysis of BPA‐PC and PET in the presence of a protic ionic salt TBD:MSA catalyst enables the selective and sequential depolymerisation of these two commonly employed polymers. Employing the same procedure, functionalised cyclic carbonates can be obtained from both mixed plastic wastes and industrial polymer blend. This methodology demonstrates that the concept of catalytic depolymerisation offers great potential for selective polymer recycling and also presents plastic waste as a “greener” alternative feedstock for the synthesis of high added value molecules.

Selective Chemical Upcycling of Mixed Plastics Guided by a Thermally Stable Organocatalyst.

Chemical recycling of plastic waste represents a greener alternative to landfill and incineration, and potentially offers a solution to the environmental consequences of increased plastic waste. Most plastics that are widely used today are designed for durability, hence currently available depolymerisation methods typically require harsh conditions and when applied to blended and mixed plastic feeds generate a mixture of products. Herein, we demonstrate that the energetic differences for the glycolysis of BPA-PC and PET in the presence of a protic ionic salt TBD:MSA catalyst enables the selective and sequential depolymerisation of these two commonly employed polymers. Employing the same procedure, functionalised cyclic carbonates can be obtained from both mixed plastic wastes and industrial polymer blend. This methodology demonstrates that the concept of catalytic depolymerisation offers great potential for selective polymer recycling and also presents plastic waste as a "greener" alternative feedstock for the synthesis of high added value molecules.

Superhydrophobic magnesium oxychloride cement based composites with integral stability and recyclability

Magnesium oxychloride (MOC) cement has attracted much interest due to the superior mechanical properties, however enhancing the poor water-resistance is facing challenges and it is worthwhile devoting much effort to it. Here, a simple method to produce MOC based composites (MOCBCs) with superhydrophobicity is proposed. The samples could maintain superhydrophobic (SHP) after bearing mechanical and chemical damages, and the SHP MOCBCs are also capable of anti-icing. Meanwhile, the modified MOCBCs overcomes the poor water-resistance, the fatal defect of MOC based materials, because the main phases are protected by hydrophobic silicone rubber. SHP ability of MOCBCs can attribute to the combination of dual-level fractal structure and addition of hydroxyl-terminated polydimethylsiloxane (HPDMS), and this characteristic helps to achieve the function of self-cleaning. Besides, the powders ground from wasted MOCBCs exhibit superhydrophobicity, suggesting the potential recyclability of this material, which can be applied to SHP coating and oil/water separation.

Recycling of hydrated Portland cement paste into new clinker

The recycling of concrete is essential because it reduces the environmental impact of concrete construction and demolition waste. For recycling, concrete waste is crushed and the coarse fraction of crushed material can be recycled as a coarse aggregate. Concrete waste fines, which are a mix of fine aggregates, coarse aggregate debris, and the hydrated cement paste, are currently not a part of the recycling process. Since hydrated cement paste has all the necessary chemical elements for clinker production but without heavy carbon dioxide emissions associated with traditional clinker raw material, it would be beneficial to recycle concrete fines for the production of clinker. However, the data available in the literature about the transformations of hydrated cement paste upon heating are contradictory. It is not clear whether hydrated cement paste can be converted back to clinker. In this research, the phase transformations in hydrated cement paste upon heating in the temperature range from 600 to 1450 °C were investigated using thermal analysis and X-ray diffractometry. The results show that hydrated Portland cement paste can be completely recovered into a new clinker using a thermal treatment. The main phase transformations during heating are described and compared to the literature data. The results indicate a great potential for the complete recycling of concrete fines for the production of cement with a low carbon footprint.

Recycling and Reuse of Sediments in Agriculture: Where Is the Problem?

Though suggested by international conventions for a long time, there are still several technical and legislative limitations to a complete reuse and recycling of dredged sediments. In particular, reuse of unpolluted sediments can be practiced, whereas sediment recycling is still affected by several downsides, and a significant proportion of the recycled fine sediments has no practical use and must be landfilled. However, the silty clayey fraction of the recycled sediments is rich in organic matter and macro- and micronutrients useful for plant growth. Nevertheless, sediment recycling in agriculture is not possible, even in non-food agricultural sectors, due to the lack of a permissive legislation and of consolidated supply chains. In addition to plant nutrients, the silty-clay sediment fraction may also accumulate organic and inorganic pollutants, and while the organic pollutants can be effectively biodegraded, metals and metalloids may concentrate at concentrations higher than the limits set by the environmental and agricultural legislations. In this paper, I briefly summarize the scientific evidence on the potential reuse and recycling of sediments in agriculture, and I discuss the main reasons for hindrance of sediment recycling in agriculture. I also present evidence from a real industrial biodegradation process that produces bioremediated fine sediment fractions with suitable properties as a mineral ingredient for plant-growing media. I propose that nutrient-rich recycled sediments could be reconsidered as a component material category in the new EU regulation on fertilizers.

Techno-economic analysis of biodiesel production over lipid extracted algae derived catalyst

The utilization of algal biomass residue after lipid extraction for other purposes can lead to maximum usage of algal biomass and economically beneficial microalgal biodiesel technology. In this study, the performance and economic potential of the conversion of Scenedesmus sp. lipids to biodiesel over lipid extracted algae (LEA) derived catalysts were investigated. The lipid extracted algae (LEA) derived catalysts (Ni/C and Ni/Fe3O4-C) were synthesized by impregnation technique and characterized using different analytical tools. The biodiesel conversion of 96.43%, 98.5% and 95.12% was achieved using biochar (C), Ni/C, and Ni/Fe3O4-C respectively under the following conditions: reaction time (4 h), temperature (60 °C), methanol to oil molar ratio (30:1) and catalyst dosage (15% w/w of oil). The findings from this study have shown that the use of lipid extracted algae derived catalysts reduced the unit production cost of microalgal biodiesel from 2.03 $/kg to (1.70–1.74 $/kg) when compared to homogeneous catalyst. Among the lipid extracted algae derived catalysts, the use of Ni/C catalyst gave the lowest unit production cost (1.70 $/kg) for biodiesel production from microalgae. The recyclability potential of the LEA derived catalysts could improve the economic viability of the process. The payback period in the range of 1.32 yr–5.57 yr obtained using LEA derived catalysts was below the lifespan of the project (10 years), suggesting that the proposed microalgal biodiesel production is economically feasible.

Solar energy-controlled shape selective synthesis of zinc oxide nanomaterials and its catalytic application in synthesis of glycerol carbonate

In this study, we have synthesized shape selective zinc oxide (ZnO) nanoflower using solar energy and naturally accessible aromatic amino acids like tryptophan, tyrosine and phenylalanine as a photo capping agents. This synthesized material has been characterized by various characterization techniques such as XRD, FE-SEM, EDX, UV–Vis and FTIR. The ZnO nanoflower synthesized using solar energy and photo capping agents exhibited excellent catalytic activity after calcination for the synthesis of glycerol carbonate via urea glycerolysis as compared to the conventional process owing to its shape selective morphology. Further, high resolution XPS studies were performed to explore the valence states and effectiveness of surface engineering of the ZnO catalyst. Such a unique technique of ZnO nanoflowers synthesis represents a novel and environmentally benign route for synthesis of shape selective metal oxide nanoparticles as well as derived nanomaterial after calcination showed excellent activity and potential recyclability for the conversion of waste into valuable products. After calcination ZnO nanomaterials shows 67% yield in the synthesis of glycerol carbonate at 140 ​°C in 4 ​h, at the end a catalytic reaction mechanism was proposed.