Circular economy as a challenging issue in social innovation area, more specifically with a focus on sustainable development, and in response to current global challenges regarding, warming, resource scarcity, attention to the environment as well as the presentation of an economic model aimed at eliminating the direct link between economic development and resource use, has been widely discussed by researchers, experts and policymakers as one of the world’, s trends. However, the concept of circular economy as a macro concept is still developing. In addition, many experts have considered the explanation of the circular economy concept to be dependent on the context of its emergence, but there is few documented research that has examined this concept in the context of innovation ecosystems. The present study tries to describe the implementation of circular innovation ecosystem with the aim of conceptualizing the circular economy in the innovation ecosystem using previous sources and experts ’, opinions. Therefore, this study, using a hybrid approach and through methods such as )1( systematic review aiming at extracting previous data, )2(content analysis aiming at examining the opinion of experts, presents the infrastructure, strategies, programs, and requirements for establishing a circular innovation ecosystem. This research stands out for a general question of what is the fundamental strategies of circular economy in implementation of circular innovation ecosystems. The results of this research will bring achievements for a wide range of researchers, policymakers in various fields, economic activists as well as institutions in charge of sustainable development.

The increasing recognition of the circular economy (CE) as a sustainable business model has spurred significant research and application across various industries. This study aims to provide a comprehensive analysis of the intersection between circular economy and sustainability, analyzing the evolving trends, key challenges, and opportunities within this domain. Through a content analysis of 112 scholarly articles published between 2022 and 2024, we delve into the fundamental components of CE and sustainability, examining their interdependencies and potential synergies. Our analysis reveals that the circular economy and sustainability are deeply interconnected, both striving for a more sustainable future. The circular economy focuses on extending the lifespan of products through strategies like design for the environment, eco-innovation, sharing economy, product lifecycle extension, recycling, upcycling, and bioeconomy. Sustainability, on the other hand, seeks a balance between environmental, social, and economic factors. Both concepts share common goals of resource efficiency, reduced pollution, social equity, and innovation. By working together, they can create a more resilient and equitable world, minimizing waste, conserving resources, and ensuring a healthier planet for future generations.

In the Algoland project, microalgae are used to clean water and air from industry. This is built on a long standing collaboration between research, industry and society. In this way Algoland supports the transition to a circular economy by turning pollution into biomass and potential products. This paper evaluates the potential for microalgae as an ecosystem service in industries from a circular economy perspective. The business model canvas was used in a workshop with stakeholders and researchers to discuss the challenges and opportunities for an industrial platform. Results showed that the established canvas model needs to be complemented by circular models; in order to be able to include ecosystem services. In this paper a circular canvas model is developed to be used in similar approaches.

Objective Circular business models are a good solution to the problems of current linear business models that cause excessive waste generation and resource scarcity. They also provide a good opportunity for businesses to gain a competitive advantage, obtain economic benefits and reduce environmental damage. To implement circular economy strategies at the business level and create a framework for better design of circular business models, the purpose of this paper is to propose a framework for identifying and classifying circular business model patterns that align with circular economy strategies. Methodology In this research, a qualitative method was applied. Sandelowski and Barros 7-step meta-synthesis method was used to identify circular business models and Nickerson taxonomy development method was used to classify circular business model patterns. Findings This study drew up a comprehensive list of 29 circular business model patterns including their name, definition, and example(s). It also proposed a comprehensive taxonomy framework for circular business model patterns based on the circular economy strategies. Under this framework, 11 dimensions for classifying 29 business model patterns were identified, including patterns for 1) dematerialization, 2) consumption efficiency, 3) circular supplies, 4) optimal production, 5) reverse and optimal logistics, 6) long-life products, 7) extending the products and parts life cycle, 8) extending materials life cycle, 9) extending resource life cycle, 10) actors of main activities in the circular value network, and 11) facilitators of activities in the circular value network. Conclusion First, the current research identified various types of circular business model patterns for the development of businesses based on a circular economy. Second, by creating a framework for classifying strategies and circular business models, it showed how to make strategies and circular business models attuned. The results of this study can help companies that intend to implement circular economy strategies in their business to identify and apply appropriate circular business models. It should be noted that the strategy of the circular value network and the patterns of the circular business model based on it, which indicate various methods of cooperation between the actors of the circular value network, were introduced for the first time in the research.

Climate change is one of the most important trends in the world. As the world grapples with the increasing impacts of climate change, the need for innovative and sustainable solutions has never been more critical. One such solution is the circular economy, a transformative approach that redefines our production and consumption systems to minimize waste, conserve resources in use, and restore natural systems. This article examines the role of the circular economy in dealing with climate change, the approaches of the circular economy are presented in this research and its concept is examined with sustainability and sustainable development, then the functions of the circular economy are analyzed and then sustainable solutions to adapt to Climate change is investigated. presented and its conceptual model is analyzed with related economic approaches and finally the relationship of each of the sustainability solutions with 10 circular economy categories is presented and emphasizes the importance of adopting this model for a sustainable future.

Circular economy is a valuable approach to achieving the concept of sustainability that promotes social equity, economic growth and development, and environmental protection. The main purpose of this study was to present a circular economy business model for knowledge-based companies. In terms of purpose, this research is in the category of fundamental-developmental research, and in terms of subject and nature, the approach of qualitative research is exploratory, and grounded theory (systematic) was used. Data were collected through documentary sources (books, articles, dissertations) and semi-structured interviews with 15 academic and non-academic experts through purposeful theoretical sampling to saturate the required information and theoretical adequacy. The data were analyzed based on grounded theory in the framework of open-source, axial, and selective codes. The results of qualitative data analysis of the research, led to the presentation of the business model of circular economy with 124 categories, 17 central categories, and 6 main factors, in the form of 6 dimensions including causal conditions (2 categories), the main phenomenon (circular business model), Strategy (4 categories), contextual characteristics (5 categories), intervening conditions (2 categories) and consequence (4 categories). The model obtained from this research can be a way for stakeholders, planners, and managers of knowledge-based companies to produce and distribute goods and services in the present century.

Objective: The construction industry is one of the largest and most energy-intensive industries in the country, contributing greatly to environmental pollution and resource waste. It can be acknowledged that the construction industry, as one of the most important and fundamental industries in the development of the country, plays a major role in the consumption of national resources and capital. The circular economy challenges the thinking of the linear economy with the aim of maximizing the use of resources and minimizing waste. Implementing a circular economy in the construction industry can bring many positive changes, but to achieve this, fundamental changes are needed in the methods of design, construction, use of resources, and innovation in business models. Strategic entrepreneurship can introduce innovative processes that help reduce costs and improve productivity in construction projects. In order for this economy to be implemented properly, there is a need to benefit from strategic entrepreneurship that can identify and exploit trends, needs, and market changes in the construction industry. Construction projects are known as one of the main sectors of the construction industry in the country, which have many impacts on the economy, environment, and society. In this regard, the use of strategic entrepreneurship in construction projects can play a key role in advancing the circular economy in the country. The aim of this research is to measure strategic entrepreneurship with a circular economy approach in construction projects.Method: The methodology used in this research is based on “Research Onion” model. The Research Onion is a six-layer model that specifies the philosophy, approach, strategy, method, time horizon, and method of collecting and analyzing research data. In the Research Onion, a study is composed of different layers, in which each layer is affected by its higher layers. These layers, which are also arranged in order of importance, are: Layer 1: Research Philosophies, Layer 2: Research Approaches, Layer 3: Research Strategies, Layer 4: Research Methods, Layer 5: Research Time Horizon, and Layer 6: Research Data Collection and Analysis Method. This research is a mixed research that uses qualitative and quantitative methods to collect and analyze data. This research was conducted in 2024. The qualitative research method includes conducting 15 semi-structured interviews with CEOs and project managers of active construction companies in residential and commercial projects in Tehran in order to apply the circular economy approach in construction projects. In conducting the interviews, Jacqueline Kramer's Ten Principles of Circular Economy were considered, and ultimately 50 themes from the application of the Ten Principles of Circular Economy were extracted from the content of the interviewees. In a quantitative research method based on the Naeji and Sayadat Strategic Entrepreneurship Questionnaire, the status of each of the five components of strategic entrepreneurship with a circular economy approach in construction projects was assessed with the participation of 85 senior managers of construction contracting companies.Results: The research findings indicate the average status of each of the five components of strategic entrepreneurship, namely Continuous innovation, Opportunity-based mindset, Proactive behaviour, Risk taking, and Capability of value creation, in the application of the circular economy approach in construction projects.Conclusion: Rethinking and effective orientation in each of the components of strategic entrepreneurship by active companies in the construction industry should be given more special attention than before.