Recent progress and challenges of MOF-based nanocomposites in bioimaging, biosensing and biocarriers for drug delivery.

Metal-organic frameworks (MOFs), a burgeoning class of coordination polymers, have garnered significant attention due to their outstanding structure, porosity, and stability. They have been extensively studied in catalysis, energy storage, water harvesting, selective gas separation, and electrochemical applications. Recent advancements in post-synthetic strategies, surface functionality, and biocompatibility have expanded the application scope of MOFs, particularly in various biomedical fields. Herein, we review MOF-based nanomaterials bioimaging nanoplatforms in magnetic resonance imaging, computed tomography, and fluorescence imaging. MOFs serve as the foundation for biosensors, demonstrating efficiency in sensing H2O2, tumor biomarkers, microRNA, and living cancer cells. MOF-based carriers are well designed in drug delivery systems and anticancer treatment therapies. Additionally, we examine the challenges and prospects of MOFs in surface modification, release of metal ions, and interaction with intracellular components, as well as their toxicity and long-term effects.

Upcycling crab shell waste into biochar for treatment of palm oil mill effluent via microwave pyrolysis and activation.

The escalating consumer demand for crabs results in a growing amount of waste, including shells, claws, and other non-edible parts. The resulting crab shell waste (CSW) is disposed of via incineration or landfills which causes environmental pollution. CSW represents a potential biological resource that can be transformed into valuable resources via pyrolysis technique. In this study, microwave pyrolysis of CSW using self-purging, vacuum, and steam activation techniques was examined to determine the biochar production yield and its performance in treating palm oil mill effluent (POME). The biochar produced through microwave pyrolysis exhibits yields ranging from 50 to 61 wt%, showing a hard texture, low volatile matter content (≤34.1 wt%), and high fixed carbon content (≥58.3 wt%). The KOH-activated biochar demonstrated a surface area of up to 177 m2/g that is predominantly composed of mesopores, providing a good amount of adsorption sites for use as adsorbent. The biochar activated with steam removed 8.3 mg/g of BOD and 42 mg/g of COD from POME. The results demonstrate that microwave pyrolysis of CSW is a promising technology to produce high-quality biochar as an adsorbent for POME treatment.

Recent progress in the production and application of biochar and its composite in environmental biodegradation.

Over the past few decades, extensive research has been conducted to develop cost-effective and high-quality biochar for environmental biodegradation purposes. Pyrolysis has emerged as a promising method for recovering biochar from biomass and waste materials. This study provides an overview of the current state-of-the-art biochar production technology, including the advancements and biochar applications in organic pollutants remediation, particularly wastewater treatment. Substantial progress has been made in biochar production through advanced thermochemical technologies. Moreover, the review underscores the importance of understanding the kinetics of pollutant degradation using biochar to maximize its synergies for potential environmental biodegradation. Finally, the study identifies the technological gaps and outlines future research advancements in biochar production and its applications for environmental biodegradation.

The use of food additives as green and environmental-friendly anti-corrosion inhibitors for protection of metals and alloys: a review.

Corrosion inhibitors have offered new opportunities to bring positive impacts on our society, especially when it has helped in protecting metals against corrosion in an aqueous solution. Unfortunately, the commonly known corrosion inhibitors used to protect metals or alloys against corrosion are invariably related to one or more drawbacks such as the employment of hazardous anti-corrosion agents, leakage of anti-corrosion agents in aqueous solution, and high solubility of anti-corrosion agents in water. Over the years, using food additives as anti-corrosion agents have drawn interest as it offers biocompatibility, less toxic, and promising applications. In general, food additives are considered safe for human consumption worldwide, and it was rigorously tested and approved by the US Food and Drug Administration. Nowadays, researchers are more interested in innovating and using green, less toxic, and economical corrosion inhibitors in metal and alloy protection. As such, we have reviewed the use of food additives to protect metals and alloys against corrosion. The current review is significant and differs from the previous review articles made on corrosion inhibitors, in which the new role of food additives is highlighted as green and environmental-friendly substances in the protection of metals and alloys against corrosion. It is anticipated that the next generation will be utilizing non-toxic and sustainable anti-corrosion agents, in which food additives might be the potential to fulfill the green chemistry goals.

Recent advances in the control of volatile organic compounds emissions from indoor wood-based panels: A comprehensive review.

Wood-based panels provide efficient alternatives to materials such as plastics derived from traditional petroleum sources and thereby help to mitigate greenhouse gas emissions. Unfortunately, using indoor manufactured panel products also results in significant emissions of volatile organic compounds including olefins, aromatic and ester compounds, which negatively affect human health. This paper highlights recent developments and notable achievements in the field of indoor hazardous air treatment technologies to guide future research toward environmentally friendly and economically feasible directions that may have a significant impact on the improvement of human settlements. Summarizing and synthesizing the principles, advantages, and limitations of different technologies can assist policymakers and engineers in identifying the most appropriate technology for a particular air pollution control program based on criteria such as cost-effectiveness, efficiency, and environmental impact. In addition, insights into the development of indoor air pollution control technologies are provided and potential areas for innovation, improvement of existing technologies, and development of new technologies are identified. Finally, the authors also hope that this sub-paper will raise public awareness of indoor air pollution issues and promote a better understanding of the importance of indoor air pollution control technologies for public health, environmental protection, and sustainable development.

Remediation and recovery of Kariba weed as emerging contaminant in freshwater and shellfish aquaculture system via solvothermal liquefaction.

Fast growing Kariba weed causes major problems and pollution on freshwater and shellfish aquaculture systems by interfering with nutrient uptake of crops, restricting sunlight penetration, and decreasing water quality due to massive biomass of Kariba weed remnants. Solvothermal liquefaction is considered an emerging thermochemical technique to convert waste into high yield of value-added products. Solvothermal liquefaction (STL) of Kariba weed as an emerging contaminant was performed to investigate the effects of different types of solvents (ethanol and methanol) and Kariba weed mass loadings (2.5-10 % w/v) on treating and reducing the weed via conversion into potentially useful crude oil product and char. Up to 92.53 % of Kariba weed has been reduced via this technique. The optimal conditions for crude oil production were found to be at 5 % w/v of mass loading in methanol medium, resulting in a high heating value (HHV) of 34.66 MJ/kg and yield of 20.86 wt%, whereas the biochar production was found to be optimum at 7.5 % w/v of mass loading in methanol medium, resulting in 29.92 MJ/kg of HHV and 25.38 wt% of yield. The crude oil consisted of beneficial chemical compounds for biofuel production such as hexadecanoic acid, methyl ester (65.02 peak area %) and the biochar showed high carbon content (72.83 %). In conclusion, STL as a remediation for emerging Kariba weed is a feasible process for shellfish aquaculture waste treatment and biofuels production.

Catalytic hydrothermal carbonization of wet organic solid waste: A review.

Hydrothermal carbonization has gained attention in converting wet organic solid waste into hydrochar with many applications such as solid fuel, energy storage material precursor, fertilizer or soil conditioner. Recently, various catalysts such as organic and inorganic catalysts are employed to guide the properties of the hydrochar. This review presents a summarize and a critical discussion on types of catalysts, process parameters and catalytic mechanisms. The catalytic impact of carboxylic acids is related to their acidity level and the number of carboxylic groups. The catalysis level with strong mineral acids is likely related to the number of hydronium ions liberated from their hydrolysis. The impact of inorganic salts is determined by the Lewis acidity of the cation. The metallic ions in metallic salts may incorporate into the hydrochar and increase the ash of the hydrochar. The selection of catalysts for various applications of hydrochars and the environmental and the techno-economic aspects of the process are also presented. Although some catalysts might enhance the characteristics of hydrochar for various applications, these catalysts may also result in considerable carbon loss, particularly in the case of organic acid catalysts, which may potentially ruin the overall advantage of the process. Overall, depending on the expected application of the hydrochar, the type of catalyst and the amount of catalyst loading requires careful consideration. Some recommendations are made for future investigations to improve laboratory-scale process comprehension and understanding of pathways as well as to encourage widespread industrial adoption.

An assessment of the efficacy of biochar and zero-valent iron nanoparticles in reducing lead toxicity in wheat (Triticum aestivum L.).

Soil heavy metal contamination is increasing rapidly due to increased anthropogenic activities. Lead (Pb) is a well-known human carcinogen causing toxic effects on humans and the environment. Its accumulation in food crops is a serious hazard to food security. Developing environment-friendly and cost-efficient techniques is necessary for Pb immobilization in the soil. A pot experiment was executed to determine the role of biochar (BC), zero-valent iron nanoparticles (n-ZVI), and zero-valent iron nanoparticles biochar composite (n-ZVI-BC) in controlling the Pb mobility and bioaccumulation in wheat (Triticum aestivum L.). The results showed that BC and n-ZVI significantly enhanced the wheat growth by increasing their photosynthetic and enzymatic activities. Among all the applied treatments, the maximum significant (p ≤ 0.05) improvement in wheat biomass was with the n-ZVI-BC application (T3). Compared to the control, the biomass of wheat roots, shoots & grains increased by 92.5, 58.8, and 49.1%, respectively. Moreover, the soil addition of T3 amendment minimized the Pb distribution in wheat roots, shoots, and grains by 33.8, 26.8, and 16.2%, respectively. The outcomes of this experiment showed that in comparison to control treatment plants, soil amendment with n-ZVI-BC (T3) increased the catalase (CAT), superoxide dismutase (SOD) activity by 49.8 and 31.1%, respectively, ultimately declining electrolyte leakage (EL), malondialdehyde (MDA) and hydrogen peroxide (H2O2) content in wheat by 38.7, 33.3, and 38%respectively. In addition, applied amendments declined the Pb mobility in the soil by increasing the residual Pb fractions. Soil amendment with n-ZVI-BC also increased the soil catalase (CAT), urease (UR), and acid phosphatase (ACP) activities by 68, 59, and 74%, respectively. Our research results provided valuable insight for the remediation of Pb toxicity in wheat. Hence, we can infer from our findings that n-ZVI-BC can be considered a propitious, environment friendly and affordable technique for mitigating Pb toxicity in wheat crop and reclamation of Pb polluted soils.

Production of highly porous biochar via microwave physiochemical activation for dechlorination in water treatment.

Most biomass is composted into low-grade biofertilizer or processed into energy fuel for burning. At the same time, waste palm shell is potentially converted into highly porous biochar for dechlorination in water treatment. A single-mode microwave activation was developed to perform microwave activation that incorporated the application of steam, KOH, and a physiochemical process. The single-mode microwave activation was performed at the activation temperature ranging from 550-600 °C and recorded a short process duration of 5 min. The steam-activated biochar showed a mass yield of 88.3 wt%, a surface area of 527.4 m2/g, and a dechlorination efficiency of 25.5 mg/g. KOH-activated biochar showed a mass yield of 90.5 wt%, a surface area of 301.1 m2/g and a dechlorination efficiency of 24.0 mg/g. The physiochemical activated biochar showed the highest pores surface area of 717.8 m2/g and dechlorination efficiency of 35.8 mg/g but the lowest mass yield of 77.6 wt%. The results demonstrate that the greater the surface area, the higher the dechlorination efficiency. Using microwave heating and physiochemical activation technology demonstrates a promising way to produce activated biochar for the dechlorination of drinking water.

The nexus between biofuels and pesticides in agroforestry: Pathways toward United Nations sustainable development goals.

The growth of global population continuously increases the demands for agroforestry-derived products, underpinning a sustainable growth of energy matrix in the sectors of food security, transportation, and industrial is momentous. The high demand for the sustainable energy sources has led to an increase in the application of pesticides associated with growing crops for the production of biofuel. In 2019, the global consumption of pesticides was 4.2 million tonnes. Case studies on life cycle assessment (LCA) of pesticides showed that toxicity is the major severe impact of pesticide usage, contributing to human toxicity (∼70%) and freshwater eco-toxicity (>50%). This alarming situation needs a solution as conventional pesticides pose various negative impacts to human and the environment, rendering the biofuel production process unsustainable. In this review, we focus on the interaction between pesticide use, biofuel production, food security for a sustainable balancing in between government benefits, environmental, and human health, aiming to track the implications and impact to the global efforts towards achieving the UN Sustainable Development Goals (SDGs). Even though, there are strict government regulations and legislations pertaining to pesticide use, and policies devised as guidelines for agroforestry sectors to implement and monitor these measures, the discrepancies still exist in between national and supranational entities. To cater the above issue, many efforts have been made to upscale the biofuel production, for example, the United States, Brazil, China and Indonesia have ventured into biofuels production from non-food-crops based feedstock while other developing nations are rapidly catching up. In this perspective, a sustainable nexus between Biofuels-Pesticides-Agroforestry (BPA) is essential to create a sustainable roadmap toward the UN SDGs, to fulfilling the energy, food, and land security. The contribution of technologies in BPA includes genetic modified crops, integrated pest and weed management with controlled release pesticides, use of nano-biopesticides is being reviewed. As a whole, the concept of biofuel processing complex (BPC) and farmers upskilling, together with the effective implementation of efficient policies and Internet of Things (IoT) would be the key to drive the BPA nexus towards fulfilment of SDGs.

Production of value-added hydrochar from single-mode microwave hydrothermal carbonization of oil palm waste for de-chlorination of domestic water.

A huge amount of palm waste generated daily represents a problematic high-moisture waste to be disposed of, yet it also represents a promising biomass resource to be transformed into a value-added product. A single-mode microwave hydrothermal carbonization process incorporating steam purging was developed and utilised to convert high-moisture palm waste into hydrochar over a range of process temperatures from 150 to 300 °C. The microwave hydrothermal carbonization recorded a shorter process duration (10 min) and prevented the occurrence of hot spots within the reactor. The resulting hydrochar showed up to 94.3 wt% of mass yield, 69.2 wt% of fixed carbon, and 412.3 m2/g of surface area. The subsequent application of the hydrochar in de-chlorination of domestic water demonstrated an impressive removal performance of up to 98.9% of free chlorine, exhibiting 435 min of breakthrough time, and 40.0 mg/g of bed capacity in continuous column operation. The results show great promise of microwave hydrothermal carbonization as a desirable approach to produce desirable hydrochar for de-chlorination application.

Progress in recycling and valorization of waste silk.

Due to the improvements in living standards and the "throw away" culture of mankind, large amount of waste textiles is constantly generated. In particular, silk is an abundant high-grade textile material with characteristics of wear comfort, high profit, and low supply with high demand, but it transforms into waste when discarded. This paper reviews the current progress of recycling and reuse of waste silk from the aspects of energy, yarn and fabric, reinforcement of composites, silk fibroin, biological tissue engineering, filtration of air and water, and electrode. The modification, optimization and application of regenerated silk fibroin extracted from waste silk are promising to industrialization and sustainable development. Making waste silk functional and intelligently wearable are two ways of recycling waste silk with low cost and high return value in the near future. The recovery and utilization of waste silk provide a paradigm for valorization of other fiber-based waste such as wool, cotton, bast and synthetic fibers.

Recent advances on botanical biosynthesis of nanoparticles for catalytic, water treatment and agricultural applications: A review.

Green synthesis of nanoparticles using plant extracts minimizes the usage of toxic chemicals or energy. Here, we concentrate on the green synthesis of nanoparticles using natural compounds from plant extracts and their applications in catalysis, water treatment and agriculture. Polyphenols, flavonoid, rutin, quercetin, myricetin, kaempferol, coumarin, and gallic acid in the plant extracts engage in the reduction and stabilization of green nanoparticles. Ten types of nanoparticles involving Ag, Au, Cu, Pt, CuO, ZnO, MgO, TiO2, Fe3O4, and ZrO2 with emphasis on their formation mechanism are illuminated. We find that green nanoparticles serve as excellent, and recyclable catalysts for reduction of nitrophenols and synthesis of organic compounds with high yields of 83-100% and at least 5 recycles. Many emerging pollutants such as synthetic dyes, antibiotics, heavy metal and oils are effectively mitigated (90-100%) using green nanoparticles. In agriculture, green nanoparticles efficiently immobilize toxic compounds in soil. They are also sufficient nanopesticides to kill harmful larvae, and nanoinsecticides against dangerous vectors of pathogens. As potential nanofertilizers and nanoagrochemicals, green nanoparticles will open a revolution in green agriculture for sustainable development.

Pilot-scale co-processing of lignocellulosic biomass, algae, shellfish waste via thermochemical approach: Recent progress and future directions.

Thermal co-processing of lignocellulosic and aquatic biomass, such as algae and shellfish waste, has shown synergistic effects in producing value-added energy products with higher process efficiency than the traditional method, highlighting the importance of scaling up to pilot-scale operations. This article discusses the design and operation of pilot-scale reactors for torrefaction, pyrolysis, and gasification, as well as the key parameters of co-processing biomass into targeted and improved quality products for use as fuel, agricultural application, and environmental remediation. Techno-economic analysis reveals that end product selling price, market dynamics, government policies, and biomass cost are crucial factors influencing the sustainability of thermal co-processing as a feasible approach to utilize the biomass. Because of its simplicity, pyrolysis allows greater energy recovery, while gasification has the highest net present value (profitability). Integration of liquefaction, hydrothermal, and fermentation pre-treatment technology has the potential to increase energy efficiency while reducing process residues.

Strategic hazard mitigation of waste furniture boards via pyrolysis: Pyrolysis behavior, mechanisms, and value-added products.

Waste furniture boards (WFBs) contain hazardous formaldehyde and volatile organic compounds when left unmanaged or improperly disposed through landfilling and open burning. In this study, pyrolysis was examined as a disposal and recovery approach to convert three types of WFBs (i.e., particleboard, plywood, and fiberboard) into value-added chemicals using thermogravimetric analysis coupled with Fourier-transform infrared spectrometry (TG-FTIR) and pyrolysis coupled with gas chromatography/mass spectrometry (Py-GC/MS). TG-FTIR analysis shows that pyrolysis performed at an optimum temperature of 250-550 °C produced volatile products mainly consisting of carbon dioxide, carbon monoxide, and light hydrocarbons, such as methane. Py-GC/MS shows that pyrolysis at different final temperatures and heating rates recovered mainly phenols (25.9-54.7%) for potential use as additives in gasoline, colorants, and food. The calorific value of WFBs ranged from 16 to 18 MJ/kg but the WFBs showed high H/C (1.7-1.8) and O/C (0.8-1.0) ratios that provide low chemical energy during combustion. This result indicates that WFBs are not recommended to be burned directly as fuel, however, they can be pyrolyzed and converted into solid pyrolytic products such as biochar with improved properties for fuel application. Hazardous components, such as cyclopropylmethanol, were removed and converted into value-added compounds, such as 1,4:3,6-dianhydro-d-glucopyranose, for use in pharmaceuticals. These results show that the pyrolysis of WFBs at high temperature and low heating rate is a promising feature to produce value-added chemicals and reduce the formation of harmful chemical species. Thus, the release of hazardous formaldehyde and greenhouse gases into the environment is redirected.

Engineering conversion of Asteraceae plants into biochars for exploring potential applications: A review.

Asteraceae presents one of the most globally prevalent, cultivated, and fundamental plant families. However, a large amount of agricultural wastes has been yearly released from Asteraceae crops, causing adverse impacts on the environment. The objective of this work is to have insights into their biomass potentials and technical possibility of conversion into biochars. Physicochemical properties are systematically articulated to orientate environmental application, soil amendment, and other utilizations. Utilizations of Asteraceae biochars in wastewater treatment can be categorized by heavy metal ions, organic dyes, antibiotics, persistent organic pollutants (POPs), and explosive compounds. Some efforts were made to analyze the production cost, as well as the challenges and prospects of Asteraceae-based biochars.

Gasification of refuse-derived fuel from municipal solid waste for energy production: a review.

Dwindling fossil fuels and improper waste management are major challenges in the context of increasing population and industrialization, calling for new waste-to-energy sources. For instance, refuse-derived fuels can be produced from transformation of municipal solid waste, which is forecasted to reach 2.6 billion metric tonnes in 2030. Gasification is a thermal-induced chemical reaction that produces gaseous fuel such as hydrogen and syngas. Here, we review refuse-derived fuel gasification with focus on practices in various countries, recent progress in gasification, gasification modelling and economic analysis. We found that some countries that replace coal by refuse-derived fuel reduce CO2 emission by 40%, and decrease the amount municipal solid waste being sent to landfill by more than 50%. The production cost of energy via refuse-derived fuel gasification is estimated at 0.05 USD/kWh. Co-gasification by using two feedstocks appears more beneficial over conventional gasification in terms of minimum tar formation and improved process efficiency.

A review on valorization of oyster mushroom and waste generated in the mushroom cultivation industry.

A review of valorization of oyster mushroom species and waste generated in the mushroom cultivation is presented, with a focus on the cultivation and valorization techniques, conditions, current research status and particularly the hazard mitigation and value-added recovery of the waste mushroom substrate (WMS) - an abundant waste in mushroom cultivation industry. Based on the studies reviewed, the production rate of the present mushroom industry is inadequate to meet market demands. There is a need for the development of new mushroom cultivation methods that can guarantee an increase in mushroom productivity and quality (nutritional and medicinal properties). This review shows that the cylindrical baglog cultivation method is more advantageous compared with the wood tray cultivation method to improve the mushroom yield and cost efficiency. Approximately 5 kg of potentially hazardous WMS (spreading diseases in mushroom farm) is generated for production of 1 kg of mushroom. This encourages various valorization of WMS for use in agricultural and energy conversion applications, mainly as biocompost, plant growing media, and bioenergy. The use of WMS as biofertilizer has shown desirable performance compared to conventional chemical fertilizer, whilst the use of WMS as energy feedstock could produce cleaner bioenergy sources compared to conventional fuels.

Applying microwave vacuum pyrolysis to design moisture retention and pH neutralizing palm kernel shell biochar for mushroom production.

Microwave vacuum pyrolysis of palm kernel shell was examined to produce engineered biochar for application as additive in agriculture application. The pyrolysis approach, performed at 750 W of microwave power, produced higher yield of porous biochar (28 wt%) with high surface area (270 cm2/g) compared to the yield obtained by conventional approach (<23 wt%). Addition of the porous biochar in mushroom substrate showed increased moisture content (99%) compared to the substrate without biochar (96%). The mushroom substrate added with biochar (150 g) was optimal in shortening formation, growth, and full colonization of the mycelium within one month. Using 2.5% of the biochar in mushroom substrate desirably maintained the optimum pH level (6.8-7) during the mycelium colonization period, leading to high mycelium growth (up to 91%) and mushroom yield (up to 280 g). The engineered biochar shows great potential as moisture retention and neutralizing agent in mushroom cultivation.

Simultaneous removal of toxic ammonia and lettuce cultivation in aquaponic system using microwave pyrolysis biochar.

This study examined an aquaponic approach of circulating water containing ammonia excretions from African catfish grown in an aquaculture tank for bacterial conversion into nitrates, which then acted as a nutrient substance to cultivate lettuce in hydroponic tank. We found that microwave pyrolysis biochar (450 g) having microporous (1.803 nm) and high BET surface area (419 m2/g) was suitable for use as biological carrier to grow nitrifying bacteria (63 g of biofilm mass) that treated the water quality through removing the ammonia (67%) and total suspended solids (68%), resulting in low concentration of remaining ammonia (0.42 mg/L) and total suspended solid (59.40 mg/L). It also increased the pH (6.8), converted the ammonia into nitrate (29.7 mg/L), and increased the nitrogen uptake by the lettuce (110 mg of nitrogen per plant), resulting in higher growth in lettuce (0.0562 %/day) while maintaining BOD5 level (3.94 mg/L) at acceptable level and 100% of catfish survival rate. Our results demonstrated that microwave pyrolysis biochar can be a promising solution for growing nitrifying bacteria in aquaponic system for simultaneous toxic ammonia remediation and generation of nitrate for growing vegetable in aquaculture industry.