Sustainable Upgrading Research Articles

Pt nanoparticles in cooperation with Mn-P composite drive base-free selective oxidation of 5-hydroxymethylfurfural

Selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) is a key approach to sustainable upgrading of furfural based biomass resources. In this work, small Pt nanoparticles (about 2.1 nm) loaded on MnPnOx composite were shown to effectively drive the base-free aerobic oxidation of HMF to FDCA in water. Regulating the P content in carrier enabled to tune HMF conversion and product distribution. The optimal Pt/MnP0.5Ox catalyst can reach 98% yield of FDCA at 110 °C under 10 bar of O2 after 24 h. It also showed the highest initial conversion rate of HMF (13 mmol molPt−1 s−1) and productivity of FDCA (4.1 mmol molPt−1 h−1) among all the Pt/MnPnOx catalysts. The carrier effect of P addition on promoting Pt oxidation catalysis was elucidated by using rigorous kinetic investigations and comprehensive characterizations. The initial conversion rate, rate constant and apparent activation energy were independently measured on oxidation of HMF and its derived intermediates. ICP-MS, XRD, TEM, H2-TPR, O2-TPD and XPS were used to acquire catalytic properties. It was demonstrated that P addition led to changes in carrier structure and metal-support interaction, which eventually promoted the formation of highly active electron-rich Pt0 sites and mobile reactive defect oxygen species. These features allowed improving the selective oxidation catalysis of supported-Pt nanoparticles for the base-free conversion of HMF to FDCA.

Investigation of organic content and microbial characteristics distribution at the pretreatment units for wastewater treatment plant sustainable upgrading

It is necessary and significant to acquire the influent characteristics in the whole pretreatment units of the activated sludge process in wastewater treatment plants (WWTPs) for the sustainable upgrading. In this work, we drawn the samples and continuously investigated all the structure units of the pretreatment section in a typical wastewater treatment plant including the anaerobic and aerobiotic treatment processes. We monitored the routine environmental parameters in the water, including dissolved oxygen (DO), pH, and suspended solids (SS). At the same time, we investigated the concentration distribution patterns of chemical oxygen demand (COD) and biochemical oxygen demand (BOD5) and found that the degradation of organic matter in the sewage continued in the pretreatment section. And the remarkable decreasing tendency of organic pollution concentration was confirmed along the flow direction in the pretreatment section, suggesting a modest depletion effect on influent organic matter of the pretreatment process. Moreover, to further validate the degradation process of organic compounds in the preprocessing procedure, analysis and detection were conducted on the types of organic compounds and the microbial community structures in the water samples collected at various sampling points through three-dimensional fluorescent spectroscopy and high-throughput sequencing, respectively. Conclusively, the detailed and accurate influent characteristics can support the scientific basis for the WWTP sustainable operation, management, and upgrading, especially for that with the low C/N ratio influent.

Electrocatalytic Upgrading of Plastic and Biomass-Derived Polyols to Formamide under Ambient Conditions.

Electrocatalytic upgrading of wasted plastic and renewable biomass represents a sustainable method to produce chemicals but is limited to carbohydrates, leaving other value-added chemicals, such as organonitrogen compounds, being scarcely explored. Herein, we reported an electrocatalytic oxidation strategy to transform polyethylene terephthalate (PET) plastic-derived ethylene glycol (EG) and biomass-derived polyols into formamide, in the presence of ammonia (NH3) over a tungsten oxide (WO3) catalyst. Taking EG-to-formamide as an example, we achieved a high formamide productivity of 537.7 μmol cm-2 h-1 with FE of 43.2 % at a constant current of 100 mA cm-2 in a flow electrolyzer with 12-h test, representing a more advantageous performance compared with previous reports for formamide electrosynthesis. Mechanistic understanding revealed that the cleavage of the C-C bond in the EG was facilitated by nucleophilic attack of in situ formed nitrogen radicals from NH3, with resultant C-N bond construction and eventually formamide production. Furthermore, this strategy can be extended to transformation of PET bottle and a series of biomass-derived polyols with carbon number from three (glycerol) to six (glucose), producing formamide with high efficiencies. This work demonstrates a sustainable upgrading strategy of plastic and biomass that may have implications to more value-added chemicals production beyond carbohydrates.

Electrocatalytic Upgrading of Plastic and Biomass‐Derived Polyols to Formamide under Ambient Conditions

AbstractElectrocatalytic upgrading of wasted plastic and renewable biomass represents a sustainable method to produce chemicals but is limited to carbohydrates, leaving other value‐added chemicals, such as organonitrogen compounds, being scarcely explored. Herein, we reported an electrocatalytic oxidation strategy to transform polyethylene terephthalate (PET) plastic‐derived ethylene glycol (EG) and biomass‐derived polyols into formamide, in the presence of ammonia (NH3) over a tungsten oxide (WO3) catalyst. Taking EG‐to‐formamide as an example, we achieved a high formamide productivity of 537.7 μmol cm−2 h−1 with FE of 43.2 % at a constant current of 100 mA cm−2 in a flow electrolyzer with 12‐h test, representing a more advantageous performance compared with previous reports for formamide electrosynthesis. Mechanistic understanding revealed that the cleavage of the C−C bond in the EG was facilitated by nucleophilic attack of in situ formed nitrogen radicals from NH3, with resultant C−N bond construction and eventually formamide production. Furthermore, this strategy can be extended to transformation of PET bottle and a series of biomass‐derived polyols with carbon number from three (glycerol) to six (glucose), producing formamide with high efficiencies. This work demonstrates a sustainable upgrading strategy of plastic and biomass that may have implications to more value‐added chemicals production beyond carbohydrates.

A binary catalytic system of sulfonated metal–organic frameworks and deep eutectic solvents towards highly efficient synthesis of 5-hydroxymethylfurfural from fructose

The green synthesis of 5-hydroxymethylfurfural (HMF) from biomass feedstocks is a crucial step for the development of sustainable fuels, resins and plastics. Here, a novel binary catalytic system was developed with metal–organic frameworks (MOFs) and deep eutectic solvents (DESs), which synergically exhibited a superior fructose dehydration efficiency with a HMF yield of 98.5% within 40 min. The replacement from terephthalic acid to 2,5-furandicarboxylic acid as the organic ligand in MOFs catalysts altered the coordination microenvironment of metal nodes, resulting in remarkably enhanced fructose conversion rates. The formation of hierarchical porous structures and moderated Brønsted acid sites in sulfonated MOFs further promoted the HMF production. Notably, HMF could be readily separated from the MOFs-DESs system and the MOF catalyst maintained stable performance after six recycles. Theoretical calculations clarified a positive correlation between the hydrogen bond interaction (between fructose and DESs components) energy and reaction efficiency. This study provided a new strategy to couple hierarchical solid acid catalysts with functional solvents binary towards effective and sustainable upgrading of biomass-derived molecules.

Interfacial high-valence Ni(IV)-enabled C-H activation for photoelectrochemical C-C bond cleavage of lignin to exclusively produce aromatic carboxylic acids

Sustainable upgrading of biomass to high-value chemicals is greatly dependent on catalytic C-C/C-O bond cleavage of high selectivity. Here, an oxidation-enhanced photoelectrochemical protocol was developed to be capable of breaking different types of C-C bonds for efficiently producing aromatic carboxylic acids (85.0–99.8% yields) from lignin. Ni local electronic state of the prepared F-Fe2O3-Co:NiOxHy with excellent durability could be modulated, and high-valence Ni(Ⅳ) reactive species played a key role in the oxidative C-C bond scission of various lignin models. In-situ characterization and control experiments indicated that photocatalytic radical and electrocatalytic interface facilitated C-H/O-H delocalization, contributing significantly to the enhanced oxidation process. In addition, quantum calculations elaborated that photo-excited holes and Ni(Ⅳ) are key reactive species for enhancive electrocatalytic cleavage of different C-C bonds in lignin to exclusively furnish aromatic carboxylic acids. This research provides a renewable funnel strategy for using solar energy to produce high-value mono-functional products from biomass.

Sustainable upgrading of crude glycerol via ultrasound-reinforced bio-refinery process with oxygen–nitrogen subsistence: Co-application of reusable heterogeneous catalyst

Selective/rapid production of value-added glyceryl triacetate (GT) from catalytic transformation of crude glycerol (CG) derived from biodiesel production procedure was systematically investigated using ultrasound-reinforced bio-refinery process with environmental friendliness. Interestingly, the tartaric-magnetic mesoporous alumina (TMMA) was synthesized via hydrothermal aluminization, calcination and functionalization, further applied as an active catalyst for CG acetylation under nitrogen and/or oxygen subsistence. The operative parameters for selective synthesis of GT derived optimization process were in the sequence of TMMA loading amount > ultrasonic level > acetylation time. The GT selectivity and activation energy derived from catalytic acetylation of CG using ultrasonic system were 97.78 % and 44.38 kJ/mol while traditional system were 52.51 % and 60.66 kJ/mol. For catalytic comparison, TMMA catalyst presented better turnover rate of CG transformation than that of marketable catalysts. Moreover, TMMA catalyst could be reused for 15 cycles without notable changing in physicochemical properties such as surface area and acidity which was contributed under oxygen subsistence by oxidative degradation, leading to long-term durability of catalytic performance and long-term repression of polymeric formation. The sustainable application of O2 molecular could perfectly restrain hard polymeric deposition on TMMA structure, leading to facile separation after complete acetylation. This work anticipated that specific integration between TMMA with CG acetylation can be further co-applied for practical process of biodiesel production using ultrasound-reinforced bio-refinery process.

Research on the mechanism and policies of polycentric agglomeration for promoting the upgrading of China's position in the global production value chain

Recently, with the increasing trend of anti-globalization, China's manufacturing industry has encountered instability in the supply of upstream products in international trade, a challenge that has given rise to an urgent demand for ways to improve China's position in the global production chain. In response to this challenge, the 14th Five-Year Plan puts forward the strategic goal of building multi-level, multi-node, networked city clusters and trade powerhouses, which provides new development opportunities for China to strengthen its position in the global production chain through the model of polycentric agglomeration. In order to gain a deeper understanding of the impact of polycentric agglomeration on the position of enterprises in the global production chain, this project will use the instrumental variable estimation method to conduct an empirical study. This method can help us accurately identify the causal relationship between polycentric agglomeration and global production chain position and assess the differential impact of different agglomeration patterns on firms' production chain position. Through this study, we expect to reveal how polycentric agglomeration can enhance firms' global production chain positions through mechanisms such as optimizing resource allocation, promoting technological innovation, and strengthening industrial chain synergies. In addition, we plan to explore the impact of polycentric agglomeration on the evolution of firms' roles in global value chains and on international trade competitiveness. The objective of this study is to provide targeted recommendations for policymakers and enterprises to help them achieve high-quality development of China's manufacturing industry by optimizing the structure of polycentric agglomeration in the context of global production chain restructuring. Through this comprehensive study, we expect to provide scientific decision support and action guidelines for China's sustainable upgrading and competitiveness enhancement in global production chains.

Techno-economic analysis of vacuum pressure swing adsorption process for a sustainable upgrading of biogas

Vacuum pressure swing adsorption (VPSA) has demonstrated promising features for the upgrading of biogas to biomethane. In this study, a biogas upgrading plant, comprised of a hybrid of an N-column VPSA unit (2 ≤N ≤ 6) with a combined heat and power (CHP) engine, was developed and its techno-economic characteristics were assessed via a mathematical approach. Moreover, the techno economic analysis was used for the state-of-the-art VPSA configuration (a sophisticated configuration) and compared with the developed hybrid process. The prominent parameters including feedstock transport, biogas production, desulfurization, drying, upgrading, combustion, and grid injection were considered in the analyses of the plant for the upgrading capacity in the range of 100–6500 Nm3/h. Sensitivity analysis of the most influencing parameters, i.e., electricity price, gas price, and feed processing revenues, was conducted for the developed models. Beside comparing upgrading cost of the sophisticated VPSA with other upgrading technologies, a detailed comparison with the best available membrane unit for biogas upgrading was conducted. The limitations of adsorption process and VPSA in reducing the upgrading cost were also investigated. The results showed that in the absence of subsidies and requirements for CO2 capture, the hybrid plant outperforms the sophisticated VPSA units. Also, higher market price of natural gas or feedstock processing revenues were necessary in order to render the plant profitable. The results showed that, at flowrates larger than 175 Nm3/h, the sophisticated VPSA unit required a lower investment cost than the membrane unit for identical outputs. The results also show that even at the most idealistic conditions in the adsorption process, the upgrading is not economically favorable without subsidies. The findings of this study shed light on the importance of process design for biogas upgrading.

Valorization of Lignocellulosic Molecules through Homogeneous Ru‐Catalyzed C−C and C−N Bond Forming Reactions

AbstractA sustainable upgrading of renewable bulk materials, obtained by decomposition of biomass lignocellulose, could facilitate their use in the industrial production of chemicals. Homogeneous ruthenium catalysis plays a fundamental role in this area. The review deals with the upgradation of lignocellulosic molecules through the formation of new C−C and C−N bonds. Selected examples of catalytic bond forming reactions reported until mid of 2023, include: (a) dehydrogenative based couplings of alcohols, (b) reductive amination of carbonyl compounds, (c) direct C−H functionalization of (hetero)aromatic compounds. These approaches fulfill the requirements of sustainability: application occurs without any previous substrate activation, thus reducing the production of waste. New chemicals containing the intrinsic molecular structure of lignocellulose substrates, showed a broad range of applications: green fuels, hydrogen carriers, monomers of polymers, intermediates of fine chemicals and pharmaceuticals. The results discussed in the review could inspire the reader to improve the valorization process, in terms of bio‐substrate scope as well as product complexity, through more strategic applications of the catalytic methods.

Sustainable upgrading of glycerol into glycidol and its derivatives under continuous-flow conditions

This study develops a safe and efficient flow process to convert glycerol, a biodiesel byproduct, into glycidol and its derivatives. The method has significant environmental and economic benefits compared to conventional glycidol synthesis routes.

Studying The Effect of Tourism Revitalization Program : Sustainable Upgrading Slums Settlements of Malang, Indonesia

Consequent of urban poverty is lack of affordable housing in urban areas. It leads to the increasing slum settlements of urban inhabitants living in deprived urban areas. Typically, slum settlements were distress and discomfort aspect on social, economic and environmental. However, policy efforts slum revitalization in Indonesia is observed to have a economic effect on the residents, where revitalization slum area of Tridi subdistrict in Malang become site tourism. Therefore, the purpose of this study is to investigate influence of revitalization slum program refer to Sustainable Development Goals (SDGs) index on development community, community behavior on environmental and ecosystem-based sustainability. This study uses a qualitative fault tree analysis (FTA) approach in sequence. Data were obtained through observation, surveys, and documentation. The results indicate a considerable built environment discomfort was due to lack of social spaces and poor design of the slum revitalization landscape. This study offers the concept of improvement strategy for slum shall not orientate to merely for beautification but also considering to improve the sustainability of the slum wellbeing.

Equitable Global Value Chain and Production Network as a Driver for Enhanced Sustainability in Developing Economies

Recent studies on the global value chain (GVC) have highlighted the need to better integrate the value chains of developing countries of the global South with that of the global North regions, which are more highly developed. This is aimed at enhancing the economic and social sustainable upgrading of the value chains of the global South regions. The paper thus seeks to answer a critical question as to whether the existing GVC set-up pertaining to global North and South countries is equitable and whether it would yield the needed socio-economic and wider sustainable benefits, particularly to global South countries. a conceptual Global Value Chain (GVC) model is developed based on the economy-wide and system-based Multi-Regional Input–Output methodology to achieve this goal. Subsequently, this was empirically tested to measure embodied flows in capital and labour for sustainable development between global North and South regions. These are achieved using the GVC networks of the UK (from the global North) and some countries in sub-Saharan Africa (from the global South) to exemplify these developments. With implications for equitable, sustainable development, our study shows significant imbalances exist in the flows of value added activities from the global South to the global North, particularly in the primary industries, which produce low-value products in their raw state. Subsequently, this creates a disproportionate economic disadvantage for South countries. As such, if global South countries are to fully benefit from GVC, the study shows that these imbalances must be addressed, such as through structural changes in the economies of global South countries from their dependencies on the primary industries.

Synergistic catalysis in loaded PtRu alloy nanoparticles to boost base-free aerobic oxidation of 5-hydroxymethylfurfural

The synergistic catalysis of dual metal sites is vital for selective activation of complicated chemical bonds in biomass compounds. The base-free selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) using air as oxidant and water as solvent is a highly sustainable upgrading process for cellulosic carbohydrates. In this work, a series of PtxRu-MgAlO (x = 0.5, 1, 2 and 3, in mole) nanocatalysts with controlled particle sizes (ca. 2 nm) were synthesized by a PVP-assisted adsorption method. The Pt2Ru-MgAlO catalyst showed 99% selectivity of FDCA with full conversion of HMF at only 100 °C under 0.2 MPa of air. In the meantime, an initial reaction rate of HMF of 2.8 mmol molM−1 s−1 and an intrinsic turnover frequency of 61.5 h−1 were attained, respectively. Besides, this catalyst exhibited superior stability during five consecutive reuses without metal leaching. It was disclosed that the Pt-Ru interaction played critical roles in determining the intrinsic activity and the CO bond activation of the prepared PtxRu-MgAlO catalysts. Kinetic experiments combined with in situ chemisorption techniques clearly unraveled adsorption and activation processes of CO bond on Pt0-Ru0 sites. To the best of our knowledge, this work firstly reported a PtRu bimetallic catalyst for aerobic oxidation of HMF and provided insight into synergistic catalysis.

Electrochemical Aldehyde Oxidation at Gold Electrodes: gem-Diol, non-Hydrated Aldehyde, and Diolate as Electroactive Species.

To date the electroactive species of selective aldehyde oxidation to carboxylates at gold electrodes is usually assumed to be the diolate. It forms with high concentration only in very alkaline electrolytes, when OH- binds to the carbonyl carbon atom. Accordingly, the electrochemical upgrading of biomass-derived aldehydes to carboxylates is believed to be limited to very alkaline electrolytes at many electrode materials. However, OH- -induced aldehyde decomposition in these electrolytes prevents application of electrochemical aldehyde oxidation for the sustainable upgrading of biomass to value-added chemicals at industrial scale. Here, we demonstrate the successful oxidation of aliphatic aldehydes at a rotating gold electrode at pH 12, where only 1 % of the aldehyde resides as the diolate species. This concentration is too small to account for the observed current, which shows that also other aldehyde species (i. e., the geminal diol and the non-hydrated aldehyde) are electroactive. This insight allows developing strategies to omit aldehyde decomposition while achieving high current densities for the selective aldehyde oxidation, making its future industrial application viable.

Correction to “Sustainable Upgrade of Bioderived Glycerol to Solketal through Acetalization over Metal-Free Mordenite Catalysts”

ADVERTISEMENT RETURN TO ARTICLES ASAPPREVCorrectionNEXTORIGINAL ARTICLEThis notice is a correctionCorrection to “Sustainable Upgrade of Bioderived Glycerol to Solketal through Acetalization over Metal-Free Mordenite Catalysts”Bhavna SainiBhavna SainiAcademy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, IndiaLight Stock Processing Division, Council of Scientific & Industrial Research-Indian Institute of Petroleum, Dehradun 248005, IndiaMore by Bhavna Saini, Anup Prakash Tathod*Anup Prakash TathodAcademy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, IndiaLight Stock Processing Division, Council of Scientific & Industrial Research-Indian Institute of Petroleum, Dehradun 248005, IndiaMore by Anup Prakash Tathodhttps://orcid.org/0000-0003-2206-1923, Sandeep K. SaxenaSandeep K. SaxenaAcademy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, IndiaLight Stock Processing Division, Council of Scientific & Industrial Research-Indian Institute of Petroleum, Dehradun 248005, IndiaMore by Sandeep K. Saxena, Selvamani ArumugamSelvamani ArumugamAcademy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, IndiaLight Stock Processing Division, Council of Scientific & Industrial Research-Indian Institute of Petroleum, Dehradun 248005, IndiaMore by Selvamani Arumugamhttps://orcid.org/0000-0002-1223-6075, and Nagabhatla Viswanadham*Nagabhatla ViswanadhamAcademy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, IndiaLight Stock Processing Division, Council of Scientific & Industrial Research-Indian Institute of Petroleum, Dehradun 248005, IndiaMore by Nagabhatla Viswanadhamhttps://orcid.org/0000-0001-8664-0399Cite this: ACS Sustainable Chem. Eng. 2023, XXXX, XXX, XXX-XXXPublication Date (Web):March 28, 2023Publication History Received2 March 2023Published online28 March 2023https://doi.org/10.1021/acssuschemeng.3c01259© 2023 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views-Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (556 KB) Get e-AlertsSUBJECTS:Alcohols,Catalysts Get e-Alerts

Urban Design Solutions for the Environmental Requalification of Informal Neighbourhoods: The George Dimitrov Neighbourhood, Maputo

The current dimension of informal settlements in Maputo requires the definition of action models framed by empirical evidence, taking advantage of pre-existing socio-spatial and environmental conditions to define physical interventions through sustainable urban design strategies, with a view to their physical (and socio-economic) upgrading. Thus, this paper highlights the potential of urban design in the environmentally sustainable upgrading of Maputo’s informal neighbourhoods. This article aimed to develop sustainable and resilient urban design proposals and identify strategies capable of guiding the future process of physical territorial transformation towards a more sustainable model. Methodologically, a literature review was undertaken for the purpose of understanding the issues related to the theme and the general characteristics of informal neighbourhoods, as well as for exploring a case study: the George Dimitrov Neighbourhood. It was concluded that the current fabric of informal settlements possesses physical characteristics which facilitate the application of sustainable and responsive urban design strategies for the requalification of these deprived areas. Despite the marked difference between the spatial configurations of informal neighbourhoods and those of formal cities, it is possible to increase the level of resilience and sustainability of informal settlements through surgical and deep solutions, anchored on the particularities of the existing fabric.

Investigating Drivers Stimulating Demand for Green Renovation of Existing Buildings and Systems

The main purpose of the research is to investigate drivers that motivate homeowners, investors, government institutions etc., to undertake green renovation. Sustainable upgrade actions have been slow although new smart  technologies such as solar panels, e-glazing, insulation systems, cogeneration etc., are developed or upgraded every year. At such a slow pace, the existing building stock presents a challenge as drivers are not rigorously identified and applied. A survey questionnaire was designed to examine all the drivers that encourage energy renovation. Extensive review of the literature provided a theoretical framework that supported the study. The survey was administered to energy consultants, architects, quantity surveyors, facility managers and engineers with sufficient professional experience. The data was analysed using means, T-test analysis and Mann–Whitney U test. The results establish a relationship between drivers and upgrade of existing buildings and systems. The findings identified a strong level of agreement among the respondents on the drivers of green renovation. Incentive and support systems, penalties for noncompliance, high energy bills, energy conservation and policy and regulations, awareness etc., are some of the motivating factors that drive energy management retrofit.

A review of sustainable technologies for energy efficient upgrade of existing buildings and systems

Sustainable upgrades include actual case studies with before and after retrofit results, case studies with simulated results and use of computer systems to predict energy savings based on exiting building parameters. In the latter no actual renovations are done thus technologies and systems are assumed. The review used real cases including simulations and adopts a mix of systematic and content analysis approaches. Thus, over 288 articles were gathered from all the major scientific journals using Scopus, ProQuest, Web of Science etc. The sample was reduced to 230 articles based on the search themes; thereafter, a detailed focus on the methods used provided basis to trim the articles to 47. Sustainable technologies identified cover those installed to the external façade, indoor areas, air filtration, insulation systems, building elements, heating, ventilation and cooling (HVAC) systems, sensors, lighting, hot and cold water systems such as boilers, chillers, pumps, motors and renewable energy technologies. The results show sustainable technologies have been used to improve various existing buildings. Also, the results indicate high rate of adoption of insulation systems for external and internal walls, roofing and ceiling elements. This paper provides evidence to support the drive towards environmental sustainability through the adoption and installation of sustainable technologies. Policies to trigger demand and installation could further improve actions towards greenhouse gas reduction.

Materials selection and installation decisions for sustainable upgrade of existing structures: Case study of Ghana

The negative effects of construction on the environment have been acknowledged all over the world. Materials and technologies are developed regularly to help address challenges posed by rising populations and related energy demands and emissions. The purpose of this study is to investigate decisions that influence materials selection for sustainable upgrade of existing structures and identify the extent to which environmental factors are applied. The study adopted a quantitative approach that involved an extensive literature review and a survey questionnaire randomly distributed to professionals in the construction industry as a way of identifying innovative sustainable upgrade decisions. A Mann-Whitey U test analysis was applied to establish decisions affecting materials selection. The results show materials selection decisions for sustainable upgrade of existing structures are focused on cost and physical properties including demand for materials, cost of sustainable upgrade, colour and texture of construction materials. Policy decisions and implementation strategies are required to improve environmental sustainability, and thereby reduce the negative effects of construction on the climate. Environmental considerations do not influence decisions on materials selection as much as cost, physical and aesthetics factors.