Springer Science and Business Media LLC

Circular economy is a widely discussed topic in the field of industrial renovation and environmentally responsive economies. The current economic and industrial model, which is termed as the produce–use–dispose model, is a linear model in which the resource is lost forever after utilisation. In addition to economic impact, disposal of the waste products creates an immense pressure on the environment. For this reason, scholars are trying to find an effective solution to this problem by ensuring the reuse of the resources that are used. The concept of the circular economy ensures the re-cycling and reuse of the resources and closes the resource loop. The circular economy challenges the produce–use–dispose concept and focuses on the reuse of resources. In a world of scarce resources, policies to recycle and reuse resources increase opportunities for economic growth. Scholars are increasingly researching the concept of a circular economy to improve efficiencies and improve industrial ecology. This study considers these ideas and identifies the opportunities and barriers of the circular economy transition. To achieve the goals of the study, the researchers reviewed 10 UK leading retailers and after the analysis have found that environmental awareness, stakeholder pressure and government rules and regulations have driven retailers to embrace the circular business model in their operations.

A new composite, itaconic acid grafted poly(vinyl) alcohol encapsulated wood pulp (IA-g-PVA-en-WP) was prepared and used for heavy metal removal [11.63 mg g−1; 93.03 % for Cd(II), 11.90 mg g−1; 95.18 % for Pb(II), and 12.14 mg g−1; 97.08 % for Ni(II)] by batch biosorption equilibrium technique. Morphological and textural features of the product were studied using SEM and BET analysis. The biosorption kinetics and thermodynamic analysis were studied for all the system to determine intraparticle and boundary layer diffusion as the rate determining steps and feasible, spontaneous and exothermic nature of biosorption at 298–318 K. The preciseness of kinetic models to experimental equilibrium data was checked by error analysis. A multilayer feed forward artificial neural network model with 15 hidden neurons at 1500 epochs was developed to predict the biosorption efficiency of the biomaterial. This model was found to be operating adequately with good correlation [R 2 = 0.997, 0.998, and 0.995 for Cd(II), Pb(II) and Ni(II)] and minimum mean square error demonstrating its good generalization potential. These findings provide an intriguing approach for the development of pre-treatment process for heavy metal decontamination from wastewater at a reduced cost.

The shortage of water worldwide is increasingly worrying. Studies in the field suggest that sustainable water resource management via water recycling is fundamental to alleviate the issue. The use of rainwater is an important alternative source that must be considered, mainly, in the water crisis facing the planet. When integrated with the concept of green roofs, the capturing and treatment of rainwater in these structures becomes an even more ecological and sustainable practice. The water drained by the roof can be used for non-potable uses, such as flushing toilet bowls. One of the main concerns when using rainwater, even for non-potable uses, is the quality of the water available, so as not to put users' health at risk. In this way, the present work proposes to experimentally analyze the quality of rainwater drained in a green roof prototype for reuse purposes. The green roof prototype was installed on an experimental bench. After each rain event (four in total), two water samples were collected in the following situations: rainwater captured directly by a container next to the bench and rainwater, drained by the green roof prototype, captured by a container through existing drains at the base of the prototype. The analyses of the collected samples were carried out at the Environmental Engineering Laboratory (LEMA/UFRJ) and performed according to the Standard Methods for the Examination of Water and Wastewater. Specifically, the experiments examine physicochemical and biological parameters following a rain event on a green roof prototype for sanitary use. Experimental results that were observed and analyzed include color, turbidity, pH, ammonia nitrogen, nitrite, nitrate, orthophosphate, total coliforms, and thermotolerant coliforms to indicate the rainwater quality from green roofs. The majority of parameters assessed were within the value thresholds indicated by the Brazilian standards, while the results of orthophosphate, fecal coliforms, color, and turbidity were not. The greatest divergence is in the concentration of orthophosphate, where a concentration of 10.88 mg/L was obtained in this experimental study, while other authors present values of 0.1 and 0.01 mg/L. Total coliforms also presented high values, but within the expected range. Comparisons with technical documents and international references related to water quality to identify possibilities of the use of rainwater were also conducted. Results indicate that the water quality has the same order of quantity for turbidity, nitrite, and ammonia nitrogen parameters across the standards. Based on such observations, filtration and disinfection processes are therefore required in the green roof system for the use of rainwater for sanitary. Finally, the experimental study of rainwater quality on the green roof presented similar results comparing with international references. The use of green roofs combined with the use of rainwater demonstrates the potential and benefits as an alternative to face the water crisis.

The use of enzyme-based products for many areas in leather making has been projected and some have found their way in commercial practices. Proteolytic and α-amylase enzymes are used in hair removal and fiber opening, respectively, producing comparable results to conventional practice of lime and sulfide-based dehairing and fiber opening. However, this process is a two-step sequence in which dehairing is performed by the proteolytic enzyme followed by fiber opening through α-amylase. In this study, an attempt has been made to achieve a single-step dehairing and fiber opening using mixed enzymes. A commercial product containing a mixture of α-amylase and protease is used for simultaneous dehairing and fiber opening of goatskins. Standardized experiments show that the leathers obtained were comparable to that of the conventionally produced leathers in terms of all the physical and bulk properties. The input–output analysis validates the observations made for dehairing and fiber opening in the preliminary trials, which are also confirmed through scanning electron micrographs. Reductions in water consumption, wastewater discharge, COD and TS loads are in the order of 30% when compared to conventional leather processing. There seems to be a significant reduction in the expenditure incurred on the leather processing upon introducing the integrated enzymatic beamhouse process.

Resource conservation for batch processes is gaining good attention in recent years. This is mainly due to the recent trend in chemical engineering that focuses on product engineering, as well as in the rise of various low volume and high value-added products (e.g. pharmaceutical, specialty chemicals, etc.) in the market. In this study, a systematic procedure to perform targeting and design of a batch resource conservation network (RCN) involving material regeneration and waste treatment (also known as a total RCN) is proposed. The procedure is applicable for all fixed-schedule-type batch RCNs with mass storage facilities. Literature examples are used to elucidate the proposed procedure.

The problem caused by large water consumption in a dyeing and finishing industrial park needs to be solved urgently. In this paper, a mathematical programming model for water integration in the dyeing and finishing industrial park (DFIP) is established. This model can optimize the water network on the basis of the minimum total annual cost. The superstructure, base of the formulas, considers shared multistage wastewater treatment facilities according to the real situation of DFIP, which is not involved in the previous study. It allows the wastewater reuse in the same plant and the water exchange with different plants. The treated water from each stage of shared multistage treatment facilities could be segregated and directed to the plants for reuse, to the next stage for advanced treatment, and/or discharged to the environment. In addition, this study also develops a water metabolism analytical method to ensure the practicability of the model. It mainly functions as analyzing the wastewater quality and water quality requirement for dyeing and finishing plant, which aims at both exploring potential water recovery and amending impractical water connections. The results obtained in a practical example indicate that the water reuse rate of the optimized water network reaches up to 73 % and the total annual cost can be decreased by 54 %.

Rice husk (RH) use in electricity generation can help mitigate environmental issues and generate profits, specifically in Rio Grande do Sul (RS) state, Brazil. The objectives of this study are to estimate the RH surplus in RS and evaluate the feasibility of its use in electricity generation. RH production in RS is estimated at 755 thousand tons per year, which is generated by 230 rice mills. Geographic Information System helped in showing RH’s power capacity for each municipality in RS. This large amount of residue has a potential output of 479.5 MW and 322.7 GWh per year. 43.1 % of this potential comes from 214 mills (93 % of total) whose power plants’ capacity is lower than 800 kW, thus classified as Micro Thermal Power Plants (MTPs). Sensitivity analysis demonstrates that the lower the MTP capacity, the more sensitive it is to economic parameters. Furthermore, all MTPs evaluated only showed profitability when Certificates of Emissions Reduction were included, showing the importance of such income. This study aims at presenting an overview of RH’s energy potential inasmuch as the upside and downside of this kind of energy system.

Cyprus continues to be one of the European Union’s most energy import-dependent countries. It is of worthy note that Cyprus is also the only European Union member state whose electricity grid is not connected to the European power network, as it uses an independent network that relies on local production. The high cost of electricity has been identified as a top problem, and officials on the island are looking at several ways to lower electricity rates. Increasing the amount of renewable energy is one of the main options being looked at. Furthermore, in a bid to meet the European Union target of 40% renewable energy electricity generation, Cyprus needs to fully utilize the vast renewable energy potential in the region. In this study, the integration of dominant renewable energy sources (solar, wind, and concentrated solar power) to the thermal power run grid system is simulated. Also, a 100% renewable energy electricity generation for 2050 is also modelled. The analysis is done, for a projected 8.3TWh/year of electricity demand, in the ENERGYPLAN simulation environment. The deterministic factors considered in this study are the power production and critical excess electricity production. Eight (8) case scenarios were developed in this study for comparative discourse of most feasible electricity generation to cut down on carbon dioxide emission in Cyprus. The optimized analysis reveals that the best case scenario for electricity generation for 2050 is Photovoltaic system integrated with the oil powered plants. This system (Photovoltaic/Oil) would generate 1.68TWh/year of renewable energy electricity. For 100% renewable energy electricity generation, the most feasible option is the Photovoltaic/Wind/storage system. This system would have an installed 4000 MW PV capacity, 7500 MW wind capacity and 30GWh storage capacity. This study gains significance as the results will give valuable technical and economic parameters that can inform policy changes in the region.

Addressing industrial carbon dioxide (CO2) emissions is imperative due to its contribution to global warming. Transitioning toward more sustainable processes, CO2 conversion technologies hold promise in generating high-value chemicals. Notably, ionic liquids (ILs) have been reported to significantly boost CO2 conversion to CO and facilitate the production of C2+ hydrocarbons within a single reactor. This study delves into the recent advancements in employing ILs for converting CO2 into CO or into C2+ hydrocarbons. Performance metrics of various catalysts, both with and without ILs, involved in the reverse water–gas shift (RWGS) reaction, are presented. Detailed insights into the underlying reaction mechanisms and thermodynamics are shared. Further, the study elaborates on the experimental procedures adopted for synthesizing IL + metal catalysts, optimally suitable for producing CO or C2+ hydrocarbons. Additionally, we report the latest accomplishments in IL-based electrochemical CO2 reduction to CO. Despite the limited availability of studies, the use of IL + metal catalysts for CO2 reduction to CO or C2+ has shown considerable promise. These advancements predominantly involve lowering the operational temperature of the reactor and enabling the production of C2+ hydrocarbons in a single unit. However, this technology is still incipient. There are crucial areas that demand further exploration, such as understanding system kinetics, thermodynamics, and enhancing process modeling and simulation. As such, this study provides a comprehensive understanding of the potential and challenges of IL-enhanced CO2 conversion, propelling future research in this field.