TECHNICAL PROGRAMME | Energy Technologies – Future Pathways
Advancing the Circular Economy & Value of Life Cycle Analyses
Forum 22 | Hall 5 Digital Poster Plaza 4
14
October
14:00
16:00
UTC+3
Life Cycle Analyses (LCA) are an essential step in designing more sustainable products and processes, which begin at resource extraction and reach end-of-life disposal. Experts will explore how LCAs inform sustainable decision-making and promote efficiencies to reduce waste. The forum will address innovative strategies for designing products and other benefits of transitioning to circular models with the support of LCAs.
The potable water supply crisis is one of the most critical environmental challenges facing humanity on a global scale. To address this issue, this study was conducted to compare the economic and environmental burdens of energy supply for a designed Reverse Osmosis System (ROS) powered by fossil fuels (Scenario 1: fossil energy supply, FE) versus solar energy (Scenario 2: fossil + solar energy supply, SE) in Larestan city, Iran. The results showed that the ROS significantly reduced water ions (by 86%), total dissolved solids (98%), electrical conductivity (97.3%), and NaCl (96.4%). Although the second scenario increased the initial capital cost by 38% compared to the first scenario, it substantially reduced environmental impacts by 20% to 73% across all categories. Under the SE scenario, the burdens on human health, ecosystems, and resources were reduced by a minimum of 43.2%. The major sources of environmental burdens in the ROS were greenhouse gas emissions (particularly CO2 and CH4), electrical conductivity, and the high temperature of the rejected water. Sensitivity analysis confirmed a 48% reduction in environmental impact under the SE scenario compared to FE. Moreover, Monte Carlo simulation revealed a coefficient of variation of less than 7% for all environmental categories, indicating the reliability and precision of the results. According to the Life Cycle Cost (LCC) analysis, the costs of water production, capital investment, and operation in the SE were 7%, 21%, and 11% higher, respectively, than those in the FE scenario. However, over a 20-year horizon, the net present value and the payback period exhibited increases of 9.34% and 1.3%, respectively, in the SE scenario relative to the FE scenario. Although the SE increased the economic costs to some extent, it significantly reduced environmental burdens. Therefore, this study provides a strategic guideline for utilizing renewable energy in water supply systems.
Effective water management remains a critical priority for the energy industry, particularly in the Sustainability and environmental management. The petroleum refining industry generates significant quantities of Titanium dioxide (TiO₂) waste from Claus catalytic processes, posing environmental and economic challenges in waste management. In alignment with sustainable water management and resource efficiency, this study introduces an innovative approach for recycling industrial TiO₂ waste by transforming it into an advanced hybrid nanophotocatalyst. The engineered photocatalyst is functionalized through a straightforward, one-pot synthesis process in which TiO₂ was hybridized with an organic polymer incorporating metal-free porphyrin as active light-harvesting centers and cyanuric chloride as linking ligands, enabling efficient photocatalytic reduction of hexavalent chromium (Cr(VI)) from contaminated wastewater under visible light irradiation. The synthesized photocatalyst was comprehensively characterized, including textural properties (N₂ adsorption–desorption isotherms), structural features (XRD and FTIR analyses), chemical composition (EDX and XPS spectroscopy), morphological characteristics (SEM and TEM imaging), optical behavior (UV-Vis diffuse reflectance spectroscopy and photoluminescence spectroscopy), and electrochemical performance (electrochemical impedance spectroscopy (EIS), transient photocurrent response, and flat band potential measurements). The hybrid photocatalyst exhibited excellent performance in the photocatalytic reduction of hexavalent chromium (Cr(VI)), achieving a reduction efficiency exceeding 99% under visible light irradiation. The synthesized photocatalyst maintained stable activity and structural integrity over five consecutive reuse cycles. Hybrid Nano-Photocatalyst, visible-light-responsive system derived from industrial TiO₂ waste, offers a sustainable and cost-effective alternative to conventional photocatalysts. To evaluate the trade-offs between the synthesized photocatalyst's environmental benefits and potential drawbacks, a comprehensive life cycle assessment (LCA) was conducted per ISO 14040/14044 using SimaPro and the Ecoinvent database. The life cycle assessment revealed the substantial impacts on marine and freshwater ecotoxicity alongside human toxicity for the removal of 1 kg chromium using as-synthesized photocatalyst. This assessment underscores the value of LCA as a decision-support tool to guide the development of more sustainable photocatalytic systems by revealing hidden environmental implications often overlooked in performance-based evaluations.
The global oil and gas construction sector, a critical driver of economic growth, faces mounting challenges due to its reliance on linear resource consumption models, resulting in excessive waste generation, environmental degradation, and unsustainable practices. This paper explores the application of a Circular Economy (CE) framework to transform waste management practices within oil and gas construction projects, particularly in emerging economies such as Brazil, Russia, India, China, and South Africa (BRICS). By adopting a lifecycle approach, the study investigates strategies to minimize resource depletion, enhance material reuse/recycling, and foster sustainable development.
Through a mixed-methods approach—including case studies, semi-structured interviews, and document analysis—the research identifies systemic inefficiencies in current waste management systems. For instance, BRICS nations exhibit alarmingly low recycling rates (e.g., 1–8% for construction waste), with most materials ending up in landfills or illegally dumped. Challenges such as inadequate regulatory frameworks, outdated technologies, and fragmented stakeholder collaboration hinder progress toward circularity. The paper proposes a Circular Economy Process Model (CEPM) tailored to oil and gas construction, emphasizing lifecycle integration, stakeholder engagement, and adaptive policies. Key strategies include adopting modular design, promoting recycled materials in infrastructure, incentivizing waste-to-energy technologies, and strengthening institutional frameworks for waste valorization.
Theoretical contributions highlight the integration of systems theory, life cycle assessment (LCA), and industrial ecology to reframe construction practices. Practically, the study offers actionable insights for policymakers and industry stakeholders, such as implementing circular procurement policies, advancing digital tools for waste tracking, and fostering cross-sector partnerships. Future applications of the CEPM could extend to other resource-intensive industries, supporting global sustainability goals.
By bridging the gap between developed and emerging economies, this research underscores the urgency of transitioning to circular practices in oil and gas construction. It provides a roadmap for reducing environmental footprints, optimizing resource use, and aligning the sector with international sustainability targets, such as the UN Sustainable Development Goals (SDGs). Ultimately, the study advocates for systemic innovation, policy coherence, and stakeholder-driven governance to achieve a resilient, low-carbon, and circular construction ecosystem in emerging markets.
Keywords: Circular economy; Construction waste management; Oil and gas projects; Sustainability; BRICS nations; Lifecycle assessment; Policy innovation.
Through a mixed-methods approach—including case studies, semi-structured interviews, and document analysis—the research identifies systemic inefficiencies in current waste management systems. For instance, BRICS nations exhibit alarmingly low recycling rates (e.g., 1–8% for construction waste), with most materials ending up in landfills or illegally dumped. Challenges such as inadequate regulatory frameworks, outdated technologies, and fragmented stakeholder collaboration hinder progress toward circularity. The paper proposes a Circular Economy Process Model (CEPM) tailored to oil and gas construction, emphasizing lifecycle integration, stakeholder engagement, and adaptive policies. Key strategies include adopting modular design, promoting recycled materials in infrastructure, incentivizing waste-to-energy technologies, and strengthening institutional frameworks for waste valorization.
Theoretical contributions highlight the integration of systems theory, life cycle assessment (LCA), and industrial ecology to reframe construction practices. Practically, the study offers actionable insights for policymakers and industry stakeholders, such as implementing circular procurement policies, advancing digital tools for waste tracking, and fostering cross-sector partnerships. Future applications of the CEPM could extend to other resource-intensive industries, supporting global sustainability goals.
By bridging the gap between developed and emerging economies, this research underscores the urgency of transitioning to circular practices in oil and gas construction. It provides a roadmap for reducing environmental footprints, optimizing resource use, and aligning the sector with international sustainability targets, such as the UN Sustainable Development Goals (SDGs). Ultimately, the study advocates for systemic innovation, policy coherence, and stakeholder-driven governance to achieve a resilient, low-carbon, and circular construction ecosystem in emerging markets.
Keywords: Circular economy; Construction waste management; Oil and gas projects; Sustainability; BRICS nations; Lifecycle assessment; Policy innovation.
Surface-facility construction in tight gas fields is capital-intensive and generates environmental impacts that span the entire life cycle, making it a critical focus for the low-carbon transition. Building on Life Cycle Analysis (LCA) and Life Cycle Cost Analysis (LCCA), this study develops a fuzzy Multi-Criteria Decision Analysis (MCDA) framework that simultaneously accounts for environmental, cost, and technical factors, thereby providing a full-life-cycle optimisation pathway for process selection.
The analysis first delineates the “well–gathering station–processing plant–pipeline network” system boundary. An LCA model constructed in SimaPro quantifies Global Warming Potential (GWP), Human Toxicity Potential (HTP) and Abiotic Depletion Potential for Elements (ADPE). These metrics are paired with an LCCA-based economic appraisal to devise phase-specific optimisation strategies for construction, operation and decommissioning. An "Environmental-Cost-Technical" multi-objective decision model is then established. Subjective weights are obtained with the Triangular Fuzzy Analytic Hierarchy Process (TFAHP); objective weights are derived with the Criteria Importance Through Intercriteria Correlation (CRITIC) method; and composite weights are calculated by minimum-deviation estimation. The Multiple-Attribute Boundary Approximation area Comparison (MABAC) method is finally used to rank alternative surface-engineering schemes.
Applying the framework to the Sulige gas field shows that the optimal configuration is “downhole throttling, multi-well manifolding, wet-gas transmission, two-stage compression, centralised processing”. During construction, integrated skid-mounted equipment cuts GWP key-factor emissions by 6.8% and HTP risk by 22.5%; in operation, green-power drives and VOC recovery reduce GWP key-factor emissions by 27.4%, HTP risk by 31.9% and ADPE consumption by 9.5%; at decommissioning, a standard steel-recycling system achieves an 80% steel recovery rate.
By quantifying environmental and economic impacts through coupled LCA-LCCA and embedding them in a fuzzy MCDA framework that addresses life-cycle cost and technical feasibility, this study offers a replicable pathway for the sustainable development of surface facilities in tight gas fields.
The analysis first delineates the “well–gathering station–processing plant–pipeline network” system boundary. An LCA model constructed in SimaPro quantifies Global Warming Potential (GWP), Human Toxicity Potential (HTP) and Abiotic Depletion Potential for Elements (ADPE). These metrics are paired with an LCCA-based economic appraisal to devise phase-specific optimisation strategies for construction, operation and decommissioning. An "Environmental-Cost-Technical" multi-objective decision model is then established. Subjective weights are obtained with the Triangular Fuzzy Analytic Hierarchy Process (TFAHP); objective weights are derived with the Criteria Importance Through Intercriteria Correlation (CRITIC) method; and composite weights are calculated by minimum-deviation estimation. The Multiple-Attribute Boundary Approximation area Comparison (MABAC) method is finally used to rank alternative surface-engineering schemes.
Applying the framework to the Sulige gas field shows that the optimal configuration is “downhole throttling, multi-well manifolding, wet-gas transmission, two-stage compression, centralised processing”. During construction, integrated skid-mounted equipment cuts GWP key-factor emissions by 6.8% and HTP risk by 22.5%; in operation, green-power drives and VOC recovery reduce GWP key-factor emissions by 27.4%, HTP risk by 31.9% and ADPE consumption by 9.5%; at decommissioning, a standard steel-recycling system achieves an 80% steel recovery rate.
By quantifying environmental and economic impacts through coupled LCA-LCCA and embedding them in a fuzzy MCDA framework that addresses life-cycle cost and technical feasibility, this study offers a replicable pathway for the sustainable development of surface facilities in tight gas fields.
With the rapid development of renewable energy and electric vehicles, traditional refining companies will face a significant impact. In 2023, China's refined oil consumption peaked, with the terminal consumption of refined oil reaching 400 million tons in 2024, a year-on-year decrease of 1.9%. The decline in refined oil demand and the addition of new production capacity have put refineries under tremendous pressure to transform. This paper explores pathways for refinery transformation by analyzing the carbon footprint of refining products. The carbon footprint of gasoline, diesel, and similar products refers to the total carbon emissions generated across their entire lifecycle, including crude oil extraction, refining, transportation, and end-use combustion. By collecting data on raw/auxiliary material consumption and energy usage in refineries, this study calculates the carbon footprint of gasoline and diesel in a typical refinery.The system boundary of this study is "from cradle to gate," divided into three stages according to the life cycle: raw material acquisition, production processing, and waste disposal. The analysis revealed that the most significant factor influencing the carbon footprint of petroleum refining products is the raw material acquisition stage (i.e., the carbon footprint of crude oil), accounting for over 50% of total emissions. This is followed by the production and processing stage (45%), while waste disposal contributes only 1%. Within the production and processing stage, primary energy sources such as natural gas account for 20%, secondary energy sources (e.g., electricity and steam) contribute 17%, and raw/auxiliary materials make up 10%. Based on this, the design of low-carbon petroleum refining products mainly focuses on the following aspects: First, reducing the use of fossil fuels, optimizing energy saving, increasing electrification rates, and using renewable energy electricity; second, increasing the use of recycled materials, such as water recycling and the recycling of catalysts and other auxiliaries. Notable practices in China include tiered utilization of wastewater to reduce freshwater consumption and recycling of spent catalysts to lower demand for new catalyst materials. These measures demonstrate practical pathways for refineries to align with low-carbon goals.
Yerzhan Abylkhanov
Chair
Oil and Gas Production Department Director
KazMunaiGas National Oil & Gas Company
Kazakhstan
Xiaoxiao Liu
Vice Chair
Vice Chief Engineer
SINOPEC Economics & Development Research Institute Company Limited
China
Salisu Isihak
Vice Chair
Senior Technical Assistant to the Managing Director, NNPC Retail,
Nigerian National Petroleum Company Ltd.
Nigeria
Bo Feng
Speaker
Deputy Director
Changqing Engineering Design Co., Ltd., Changqing Oilfield, China National Petroleum Corporation (CNPC)
China
Surface-facility construction in tight gas fields is capital-intensive and generates environmental impacts that span the entire life cycle, making it a critical focus for the low-carbon transition. Building on Life Cycle Analysis (LCA) and Life Cycle Cost Analysis (LCCA), this study develops a fuzzy Multi-Criteria Decision Analysis (MCDA) framework that simultaneously accounts for environmental, cost, and technical factors, thereby providing a full-life-cycle optimisation pathway for process selection.
The analysis first delineates the “well–gathering station–processing plant–pipeline network” system boundary. An LCA model constructed in SimaPro quantifies Global Warming Potential (GWP), Human Toxicity Potential (HTP) and Abiotic Depletion Potential for Elements (ADPE). These metrics are paired with an LCCA-based economic appraisal to devise phase-specific optimisation strategies for construction, operation and decommissioning. An "Environmental-Cost-Technical" multi-objective decision model is then established. Subjective weights are obtained with the Triangular Fuzzy Analytic Hierarchy Process (TFAHP); objective weights are derived with the Criteria Importance Through Intercriteria Correlation (CRITIC) method; and composite weights are calculated by minimum-deviation estimation. The Multiple-Attribute Boundary Approximation area Comparison (MABAC) method is finally used to rank alternative surface-engineering schemes.
Applying the framework to the Sulige gas field shows that the optimal configuration is “downhole throttling, multi-well manifolding, wet-gas transmission, two-stage compression, centralised processing”. During construction, integrated skid-mounted equipment cuts GWP key-factor emissions by 6.8% and HTP risk by 22.5%; in operation, green-power drives and VOC recovery reduce GWP key-factor emissions by 27.4%, HTP risk by 31.9% and ADPE consumption by 9.5%; at decommissioning, a standard steel-recycling system achieves an 80% steel recovery rate.
By quantifying environmental and economic impacts through coupled LCA-LCCA and embedding them in a fuzzy MCDA framework that addresses life-cycle cost and technical feasibility, this study offers a replicable pathway for the sustainable development of surface facilities in tight gas fields.
The analysis first delineates the “well–gathering station–processing plant–pipeline network” system boundary. An LCA model constructed in SimaPro quantifies Global Warming Potential (GWP), Human Toxicity Potential (HTP) and Abiotic Depletion Potential for Elements (ADPE). These metrics are paired with an LCCA-based economic appraisal to devise phase-specific optimisation strategies for construction, operation and decommissioning. An "Environmental-Cost-Technical" multi-objective decision model is then established. Subjective weights are obtained with the Triangular Fuzzy Analytic Hierarchy Process (TFAHP); objective weights are derived with the Criteria Importance Through Intercriteria Correlation (CRITIC) method; and composite weights are calculated by minimum-deviation estimation. The Multiple-Attribute Boundary Approximation area Comparison (MABAC) method is finally used to rank alternative surface-engineering schemes.
Applying the framework to the Sulige gas field shows that the optimal configuration is “downhole throttling, multi-well manifolding, wet-gas transmission, two-stage compression, centralised processing”. During construction, integrated skid-mounted equipment cuts GWP key-factor emissions by 6.8% and HTP risk by 22.5%; in operation, green-power drives and VOC recovery reduce GWP key-factor emissions by 27.4%, HTP risk by 31.9% and ADPE consumption by 9.5%; at decommissioning, a standard steel-recycling system achieves an 80% steel recovery rate.
By quantifying environmental and economic impacts through coupled LCA-LCCA and embedding them in a fuzzy MCDA framework that addresses life-cycle cost and technical feasibility, this study offers a replicable pathway for the sustainable development of surface facilities in tight gas fields.
The potable water supply crisis is one of the most critical environmental challenges facing humanity on a global scale. To address this issue, this study was conducted to compare the economic and environmental burdens of energy supply for a designed Reverse Osmosis System (ROS) powered by fossil fuels (Scenario 1: fossil energy supply, FE) versus solar energy (Scenario 2: fossil + solar energy supply, SE) in Larestan city, Iran. The results showed that the ROS significantly reduced water ions (by 86%), total dissolved solids (98%), electrical conductivity (97.3%), and NaCl (96.4%). Although the second scenario increased the initial capital cost by 38% compared to the first scenario, it substantially reduced environmental impacts by 20% to 73% across all categories. Under the SE scenario, the burdens on human health, ecosystems, and resources were reduced by a minimum of 43.2%. The major sources of environmental burdens in the ROS were greenhouse gas emissions (particularly CO2 and CH4), electrical conductivity, and the high temperature of the rejected water. Sensitivity analysis confirmed a 48% reduction in environmental impact under the SE scenario compared to FE. Moreover, Monte Carlo simulation revealed a coefficient of variation of less than 7% for all environmental categories, indicating the reliability and precision of the results. According to the Life Cycle Cost (LCC) analysis, the costs of water production, capital investment, and operation in the SE were 7%, 21%, and 11% higher, respectively, than those in the FE scenario. However, over a 20-year horizon, the net present value and the payback period exhibited increases of 9.34% and 1.3%, respectively, in the SE scenario relative to the FE scenario. Although the SE increased the economic costs to some extent, it significantly reduced environmental burdens. Therefore, this study provides a strategic guideline for utilizing renewable energy in water supply systems.
Kurmanbek Yeshmagambetov
Speaker
Head of Standarts and Innovation Department
KazTransOil JSC
Kazakhstan
The global oil and gas construction sector, a critical driver of economic growth, faces mounting challenges due to its reliance on linear resource consumption models, resulting in excessive waste generation, environmental degradation, and unsustainable practices. This paper explores the application of a Circular Economy (CE) framework to transform waste management practices within oil and gas construction projects, particularly in emerging economies such as Brazil, Russia, India, China, and South Africa (BRICS). By adopting a lifecycle approach, the study investigates strategies to minimize resource depletion, enhance material reuse/recycling, and foster sustainable development.
Through a mixed-methods approach—including case studies, semi-structured interviews, and document analysis—the research identifies systemic inefficiencies in current waste management systems. For instance, BRICS nations exhibit alarmingly low recycling rates (e.g., 1–8% for construction waste), with most materials ending up in landfills or illegally dumped. Challenges such as inadequate regulatory frameworks, outdated technologies, and fragmented stakeholder collaboration hinder progress toward circularity. The paper proposes a Circular Economy Process Model (CEPM) tailored to oil and gas construction, emphasizing lifecycle integration, stakeholder engagement, and adaptive policies. Key strategies include adopting modular design, promoting recycled materials in infrastructure, incentivizing waste-to-energy technologies, and strengthening institutional frameworks for waste valorization.
Theoretical contributions highlight the integration of systems theory, life cycle assessment (LCA), and industrial ecology to reframe construction practices. Practically, the study offers actionable insights for policymakers and industry stakeholders, such as implementing circular procurement policies, advancing digital tools for waste tracking, and fostering cross-sector partnerships. Future applications of the CEPM could extend to other resource-intensive industries, supporting global sustainability goals.
By bridging the gap between developed and emerging economies, this research underscores the urgency of transitioning to circular practices in oil and gas construction. It provides a roadmap for reducing environmental footprints, optimizing resource use, and aligning the sector with international sustainability targets, such as the UN Sustainable Development Goals (SDGs). Ultimately, the study advocates for systemic innovation, policy coherence, and stakeholder-driven governance to achieve a resilient, low-carbon, and circular construction ecosystem in emerging markets.
Keywords: Circular economy; Construction waste management; Oil and gas projects; Sustainability; BRICS nations; Lifecycle assessment; Policy innovation.
Through a mixed-methods approach—including case studies, semi-structured interviews, and document analysis—the research identifies systemic inefficiencies in current waste management systems. For instance, BRICS nations exhibit alarmingly low recycling rates (e.g., 1–8% for construction waste), with most materials ending up in landfills or illegally dumped. Challenges such as inadequate regulatory frameworks, outdated technologies, and fragmented stakeholder collaboration hinder progress toward circularity. The paper proposes a Circular Economy Process Model (CEPM) tailored to oil and gas construction, emphasizing lifecycle integration, stakeholder engagement, and adaptive policies. Key strategies include adopting modular design, promoting recycled materials in infrastructure, incentivizing waste-to-energy technologies, and strengthening institutional frameworks for waste valorization.
Theoretical contributions highlight the integration of systems theory, life cycle assessment (LCA), and industrial ecology to reframe construction practices. Practically, the study offers actionable insights for policymakers and industry stakeholders, such as implementing circular procurement policies, advancing digital tools for waste tracking, and fostering cross-sector partnerships. Future applications of the CEPM could extend to other resource-intensive industries, supporting global sustainability goals.
By bridging the gap between developed and emerging economies, this research underscores the urgency of transitioning to circular practices in oil and gas construction. It provides a roadmap for reducing environmental footprints, optimizing resource use, and aligning the sector with international sustainability targets, such as the UN Sustainable Development Goals (SDGs). Ultimately, the study advocates for systemic innovation, policy coherence, and stakeholder-driven governance to achieve a resilient, low-carbon, and circular construction ecosystem in emerging markets.
Keywords: Circular economy; Construction waste management; Oil and gas projects; Sustainability; BRICS nations; Lifecycle assessment; Policy innovation.
Wenjia Xu
Speaker
Senior Engineer
CNPC Research Institute of Safety & Environment Technology
China
With the rapid development of renewable energy and electric vehicles, traditional refining companies will face a significant impact. In 2023, China's refined oil consumption peaked, with the terminal consumption of refined oil reaching 400 million tons in 2024, a year-on-year decrease of 1.9%. The decline in refined oil demand and the addition of new production capacity have put refineries under tremendous pressure to transform. This paper explores pathways for refinery transformation by analyzing the carbon footprint of refining products. The carbon footprint of gasoline, diesel, and similar products refers to the total carbon emissions generated across their entire lifecycle, including crude oil extraction, refining, transportation, and end-use combustion. By collecting data on raw/auxiliary material consumption and energy usage in refineries, this study calculates the carbon footprint of gasoline and diesel in a typical refinery.The system boundary of this study is "from cradle to gate," divided into three stages according to the life cycle: raw material acquisition, production processing, and waste disposal. The analysis revealed that the most significant factor influencing the carbon footprint of petroleum refining products is the raw material acquisition stage (i.e., the carbon footprint of crude oil), accounting for over 50% of total emissions. This is followed by the production and processing stage (45%), while waste disposal contributes only 1%. Within the production and processing stage, primary energy sources such as natural gas account for 20%, secondary energy sources (e.g., electricity and steam) contribute 17%, and raw/auxiliary materials make up 10%. Based on this, the design of low-carbon petroleum refining products mainly focuses on the following aspects: First, reducing the use of fossil fuels, optimizing energy saving, increasing electrification rates, and using renewable energy electricity; second, increasing the use of recycled materials, such as water recycling and the recycling of catalysts and other auxiliaries. Notable practices in China include tiered utilization of wastewater to reduce freshwater consumption and recycling of spent catalysts to lower demand for new catalyst materials. These measures demonstrate practical pathways for refineries to align with low-carbon goals.
Effective water management remains a critical priority for the energy industry, particularly in the Sustainability and environmental management. The petroleum refining industry generates significant quantities of Titanium dioxide (TiO₂) waste from Claus catalytic processes, posing environmental and economic challenges in waste management. In alignment with sustainable water management and resource efficiency, this study introduces an innovative approach for recycling industrial TiO₂ waste by transforming it into an advanced hybrid nanophotocatalyst. The engineered photocatalyst is functionalized through a straightforward, one-pot synthesis process in which TiO₂ was hybridized with an organic polymer incorporating metal-free porphyrin as active light-harvesting centers and cyanuric chloride as linking ligands, enabling efficient photocatalytic reduction of hexavalent chromium (Cr(VI)) from contaminated wastewater under visible light irradiation. The synthesized photocatalyst was comprehensively characterized, including textural properties (N₂ adsorption–desorption isotherms), structural features (XRD and FTIR analyses), chemical composition (EDX and XPS spectroscopy), morphological characteristics (SEM and TEM imaging), optical behavior (UV-Vis diffuse reflectance spectroscopy and photoluminescence spectroscopy), and electrochemical performance (electrochemical impedance spectroscopy (EIS), transient photocurrent response, and flat band potential measurements). The hybrid photocatalyst exhibited excellent performance in the photocatalytic reduction of hexavalent chromium (Cr(VI)), achieving a reduction efficiency exceeding 99% under visible light irradiation. The synthesized photocatalyst maintained stable activity and structural integrity over five consecutive reuse cycles. Hybrid Nano-Photocatalyst, visible-light-responsive system derived from industrial TiO₂ waste, offers a sustainable and cost-effective alternative to conventional photocatalysts. To evaluate the trade-offs between the synthesized photocatalyst's environmental benefits and potential drawbacks, a comprehensive life cycle assessment (LCA) was conducted per ISO 14040/14044 using SimaPro and the Ecoinvent database. The life cycle assessment revealed the substantial impacts on marine and freshwater ecotoxicity alongside human toxicity for the removal of 1 kg chromium using as-synthesized photocatalyst. This assessment underscores the value of LCA as a decision-support tool to guide the development of more sustainable photocatalytic systems by revealing hidden environmental implications often overlooked in performance-based evaluations.
