Sustainability considerations of green buildings: a detailed overview on current advancements and future considerations

The concept of green building has gradually formed with the increase in public awareness of environmental protection, which also covers a wide range of elements. The green building is the fundamental platform of sustainable development. This review paper provides solutions for the multi-dimensional and balanced development of green building. Since green building is the development trend of the construction industry, it presents an opportunity to mitigate global warming and accomplish energy efficiency. However, the problem is that the development of green building’s implementation is restricted by the lack of government policies, imperfect technical abilities and unreasonable economic benefits. One conclusion drawn from the results shows that the benefits of green building implementation include environmental, economic, social, and health and safety aspects. Moreover, it is crucial to improve the awareness of stakeholders to promote the development process of green building. The government should launch campaigns to encourage developers and tenants to embrace green building, which can add value to buildings. The novelty of the paper provides a more systematic review on the sustainable considerations of green building than previous efforts in the literature. Bibliometric analysis is conducted through VOS viewer software. This review paperdiscusses the relevant benefits and challenges of green building through a critical review of existing research knowledge related to green building. The current advancements in green building are highlighted in this paper. Importantly, future recommendations for standards and policy formulation and future research directions are proposed in this review article

Synthesis of Enzyme-based Organic-Inorganic Hybrid Nanoflower Particles

Enzyme-incorporated hybrid nanostructures are the immobilization of enzymes and inorganic components that exhibits promising characteristics in various industries. The immobilization of enzymes onto nanomaterial is naturally based to accommodate the enzymatic activity, stability, recyclability as well as their catalytic functions. The designing of these conjugates can improve the overall enzymatic performance by imparting their novel properties onto the system in comparison to conventional free enzymes which experience drawbacks in terms of deactivation or denaturing. A facile and ultrafast method is described in this paper to synthesize a novel enzyme-incorporated lipase/Cu3(PO4)2 hybrid nanoflower (NF). The physical properties of the hybrid NF allow easier retrieval which indicates its higher reusability and recyclability value. The enzyme loading capacity was found to be 95.1% whereas, the catalytic performance of lipase/Cu3(PO4)2 hybrid NF at the optimal conditions resulted in a specific enzyme activity of 1752 U/g corresponding to an increment of 90.5% to that of free lipase. This indicates that the well-designed lipase/Cu3(PO4)2 hybrid NF to be highly efficient in industrial biocatalytic applications. Meanwhile, in future work, we aim to study its operational stability and reusability to enzymatically degrade biopolymers through hydrolysis process

Machine learning and computational chemistry to improve biochar fertilizers : a review

Traditional fertilizers are highly inefficient, with a major loss of nutrients and associated pollution. Alternatively, biochar loaded with phosphorous is a sustainable fertilizer that improves soil structure, stores carbon in soils, and provides plant nutrients in the long run, yet most biochars are not optimal because mechanisms ruling biochar properties are poorly known. This issue can be solved by recent developments in machine learning and computational chemistry. Here we review phosphorus-loaded biochar with emphasis on computational chemistry, machine learning, organic acids, drawbacks of classical fertilizers, biochar production, phosphorus loading, and mechanisms of phosphorous release. Modeling techniques allow for deciphering the influence of individual variables on biochar, employing various supervised learning models tailored to different biochar types. Computational chemistry provides knowledge on factors that control phosphorus binding, e.g., the type of phosphorus compound, soil constituents, mineral surfaces, binding motifs, water, solution pH, and redox potential. Phosphorus release from biochar is controlled by coexisting anions, pH, adsorbent dosage, initial phosphorus concentration, and temperature. Pyrolysis temperatures below 600 °C enhance functional group retention, while temperatures below 450 °C increase plant-available phosphorus. Lower pH values promote phosphorus release, while higher pH values hinder it. Physical modifications, such as increasing surface area and pore volume, can maximize the adsorption capacity of phosphorus-loaded biochar. Furthermore, the type of organic acid affects phosphorus release, with low molecular weight organic acids being advantageous for soil utilization. Lastly, biochar-based fertilizers release nutrients 2–4 times slower than conventional fertilizers

Technologies for removing pharmaceuticals and personal care products (PPCPs) from aqueous solutions: Recent advances, performances, challenges and recommendations for improvements

In recent years, the removal of pharmaceutical and personal care products (PPCPs) from aqueous solutions has been gaining a lot of attention from researchers throughout the world. This is particularly due to the concern about their potential hazards and toxicities, as they are classified as emerging contaminants. Thus, there is an increasing need to investigate removal technologies for PPCPs at a deeper and more holistic level. This review aims to provide the latest developments in removal technologies for PPCPs. It first succinctly describes the types, characteristics, and hazards of PPCPs on the environment and human health. It then comprehensively covers a wide range of technologies for removing PPCPs from aqueous solutions, comprising the adsorption process (using carbon-based adsorbents, plant biomasses, clay and clay minerals, silica-based adsorbents, zeolite-based adsorbents, polymers and resins, and hybrid adsorbents), advanced oxidation processes (AOPs) (photocatalysis, Fenton or photo-Fenton or electro-Fenton, ozonation, ultrasonication, electrochemical oxidation, persulfate oxidation), membrane separation processes (ultrafiltration, nanofiltration, reverse osmosis), biodegradation processes (bacteria, fungi, and algae), and hybrid treatment (adsorption-AOP, AOP-membrane, membrane-biodegradation, and others). According to the specific experimental conditions, the reported removal efficiencies for adsorption, AOPs, membrane processes, biodegradation processes and hybrid treatment were 40–100%, 40–100%, 3–100%, 14–100% and 5–100%, respectively. This review paper also highlights the challenges in this field of research, particularly incomplete removal of certain PPCPs, high costs of some treatment technologies and generally insufficient understanding on the removal kinetics and mechanisms of PPCPs. This review offers recommendations for future works to further advance the technical performances to eventually realize the wider application of these technologies at the industrial scale

Immobilized enzyme/microorganism complexes for degradation of microplastics: A review of recent advances, feasibility and future prospects

Environmental prevalence of microplastics has prompted the development of novel methods for their removal, one of which involves immobilization of microplastics-degrading enzymes. Various materials including nanomaterials have been studied for this purpose but there is currently a lack of review to present these studies in an organized manner to highlight the advances and feasibility. This article reviewed more than 100 peer-reviewed scholarly papers to elucidate the latest advances in the novel application of immobilized enzyme/microorganism complexes for microplastics degradation, its feasibility and future prospects. This review shows that metal nanoparticle-enzyme complexes improve biodegradation of microplastics in most studies through creating photogenerated radicals to facilitate polymer oxidation, accelerating growth of bacterial consortia for biodegradation, anchoring enzymes and improving their stability, and absorbing water for hydrolysis. In a study, the antimicrobial property of nanoparticles retarded the growth of microorganisms, hence biodegradation. Carbon particle-enzyme complexes enable enzymes to be immobilized on carbon-based support or matrix through covalent bonding, adsorption, entrapment, encapsulation, and a combination of the mechanisms, facilitated by formation of cross-links between enzymes. These complexes were shown to improve microplastics-degrading efficiency and recyclability of enzymes. Other emerging nanoparticles and/or enzymatic technologies are fusion of enzymes with hydrophobins, polymer binding module, peptide and novel nanoparticles. Nonetheless, the enzymes in the complexes present a limiting factor due to limited understanding of the degradation mechanisms. Besides, there is a lack of studies on the degradation of polypropylene and polyvinyl chloride. Genetic bioengineering and metagenomics could provide breakthrough in this area. This review highlights the optimism of using immobilized enzymes/microorganisms to increase the efficiency of microplastics degradation but optimization of enzymatic or microbial activities and synthesis of immobilized enzymes/microorganisms are crucial to overcome the barriers to their wide application

Nitrogen-doped titanium dioxide supported on activated carbon for synergistic removal of aqueous organic pollutants

In recent years, increasing global water scarcity has resulted in intense research to improve the quantity and quality of drinking water. Adsorption via activated carbon (AC) is a proven technology for water treatment and reclamation, while heterogeneous photocatalysis using titanium dioxide (TiO2) is highly energy-efficient in degrading and mineralizing various recalcitrant organic pollutants. Thus, the coupled adsorption-solar photocatalysis processes potentially present an environmentally-friendly and cost-effective treatment technology for water reclamation and reuse. This study therefore focused on developing a novel bifunctional adsorptive-photocatalytic material which was photoexcitable under solar light irradiation. In this study, various types of nitrogen-doped TiO2 supported on powdered AC (N-TiO2/AC) composites were synthesized via the modified sol-gel techniques. These include the composites prepared via single-stage calcination, two-stage calcination, and also facile techniques incorporating commercial titania P25 (N-P25-TiO2/AC). The composites were characterized using X-ray diffraction (XRD), porosimetry, UV-Vis spectrophotometry, electrophoretic mobility measurement, Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy coupled with energy-dispersive X-ray (SEM/EDX), and transmission electron microscopy (TEM). Three aqueous recalcitrant organic pollutants of varying molecular properties, namely bisphenol-A (BPA), sulfamethazine (SMZ), and clofibric acid (CFA), were chosen as the model pollutants in this study.Doctor of Philosophy (CEE

Solar regeneration of powdered activated carbon impregnated with visible-light responsive photocatalyst : factors affecting performances and predictive model

This study demonstrated a green technique to regenerate spent powdered activated carbon (AC) using solar photocatalysis. The AC was impregnated with a photocatalyst photoexcitable under visible-light irradiation to yield a solar regenerable composite, namely nitrogen-doped titanium dioxide (N-TiO2/AC). This composite exhibited bifunctional adsorptive-photocatalytic characteristics. Contaminants of emerging environmental concern, i.e. bisphenol-A (BPA), sulfamethazine (SMZ) and clofibric acid (CFA) which exhibited varying affinities for AC were chosen as target pollutants. The adsorption of BPA and SMZ by the N-TiO2/AC was significantly higher than that of CFA. The performance of solar photocatalytic regeneration (SPR) of the spent N-TiO2/AC composite generally increased with light intensity, N-TiO2 loading and temperature. The regeneration efficiency (RE) for CFA-loaded spent composite was the highest compared to the other pollutant-loaded spent composites, achieving 77% within 8 h of solar irradiation (765 W m−2). The rate-limiting process was pollutant desorption from the interior AC sorption sites. A kinetic model was developed to predict the transient concentration of the sorbate remaining in the spent composite during SPR. Comparison studies using solvent extraction technique indicated a different order of RE for the three pollutants, attributable to their varying solubilities in the aqueous and organic solvents

Biosorption of heavy metals from aqueous solution by various chemically modified agricultural wastes : a review

In recent years, with the global increase in industrialization, there has been a significant increase in the amount of toxic pollutants such as heavy metals being released into water bodies. Adsorption is considered as one of the most attractive methods due to its high efficiency and ability to remove heavy metals even at low concentration. Agricultural wastes-based biosorbents have attracted great interest due to their capability to effectively remove heavy metals from wastewater. Chemical modifications on biosorbents can significantly improve the biosorption capacities and the longevity of the biosorbents. Most of the adsorption studies followed the Langmuir and Freundlich adsorption isotherm models. The pseudo-second-order kinetic model best fitted most of the adsorption kinetic studies. Moreover, ion exchange, electrostatic attraction and chelation were the governing adsorption mechanisms in most of the studies. The adsorption process was usually spontaneous and endothermic in nature. The regeneration of biosorbents was most effective when acids were used as eluents and this had allowed some biosorbents to be reused efficiently up to 10 times. To elucidate a practical perspective, analysis on column studies, adsorption performance using industrial wastewater, and cost analysis had been conducted. Cost analysis proved that agricultural wastes-based biosorbents are cheaper than traditional adsorbents such as activated carbon. © 2021 Elsevier Lt

Bimodal N-doped P25-TiO2/AC composite : preparation, characterization, physical stability, and synergistic adsorptive-solar photocatalytic removal of sulfamethazine

A novel nitrogen-doped P25-TiO2 of bimodal structure with activated carbon supported (N-P25-TiO2/AC) was synthesized via the modified sol–gel techniques. Besides adding urea as N-source, the N-doping could also be induced through calcination under mixed NH3/N2 atmosphere. The composite was characterized using XRD, porosimetry, UV–vis spectrophotometry, FTIR, XPS, SEM/EDX and TEM. The physical stability of the composite was examined through ultrasonication disruption, and the composite exhibited good physical stability. The synergistic effects of the adsorption-solar photocatalysis of sulfamethazine (SMZ) as exhibited by the composites were examined. The best performing bimodal composite was N-P25-TiO2 (25 + 10)/AC, which comprised 25% of N-P25 and 10% N-TiO2 (sol) by weight composition (wt%). The maximum adsorption capacity (Smax) for the N-P25-TiO2 (25 + 10)/AC, at pH 3.0, 6.0 and 10.0 was 183 ± 3, 194 ± 3, and 103 ± 2 mg g−1, respectively. The effects of the total loading of N-doped titania, sol–gel synthesis technique, weight distribution of N-P25 and N-TiO2 (sol), composite dosage, light wavelength spectrum and solution pH on the photocatalytic degradation (PCD) of SMZ were investigated. The N-P25-TiO2 (25 + 10)/AC composite exhibited enhanced PCD efficiency under solar irradiation with a pseudo first-order rate constant (kapp) of 0.48 h−1, as compared to other types of bimodal composites because its higher N-P25 content led to a greater photocatalytic activity