Waste Remediation Research Articles

How Ir‐Rh Alloys Improve Electrochemical Ammonia Oxidation Activity Studied by Density Functional Theory

The electrochemical ammonia oxidation reaction (AOR) has applications in hydrogen storage and ammonia waste remediation. Using density functional theory, we investigate the mechanism of AOR on Ir, Rh, and their alloys at varied atomic ratios (Ir75Rh25, Ir50Rh50, and Ir25Rh75) towards N2(g), NO2–(aq), and NO3–(aq) formation. This work introduces a method for computational alloy design by considering both electronic energy and configurational entropy. The structures considered are selective to N2(g) formation and all favoured *N‐N coupling. An Ir50Rh50 alloy was found to reduce the theoretical onset potential for N2(g) formation relative to pure Ir while not exhibiting a downhill coupling step corresponding to catalyst poisoning by *N as shown for pure Rh, consistent with previous experimental work. The formation of NO2–(aq) and NO3–(aq) demand significantly higher potentials, typically limited by the final hydroxylation step before desorption.

Unravelling the detoxification trail of potential toxic heavy metals: an insight into heavy metal auditing and ecological health upon valorisation by Lampito mauritii and Eudrilus eugeniae.

Evidence on prospective remediation of municipal solid waste contaminated with toxic heavy metals by Eudrilus eugeniae (Eu) and Lampito mauritii (L) is very scarce and yet to be explored. In this study, heavy metal detoxification potential of E. eugeniae and L. mauritii in municipal solid waste (MSW) + cowdung (CD) (3:1)-based feedstocks were investigated against Eisenia fetida (E) (a well-known vermi-remediator) and aerobic composting. Excellent reduction (70.01-93.04%) of potentially toxic heavy metals (PTHMs) (Pb, Cr, Cd and Zn) were evident in both E. eugeniae and L. mauritii employed treatments. Moreover, the results on heavy metal budget quotient clearly demonstrated the unique detoxification route undertaken by E. eugeniae and L. mauritii via humic composite facilitated chelation over the nominal bioaccumulation pathway. The principal component analysis (PCA) confirmed the strong negative correlation between the heavy metal (HM) level in earthworm gut and MSW substrate, whereas a strong positive correlation between humic substances and HM remediation. Furthermore, analysis of ecological health parameters indicated substantial reduction of environmental risk and guaranteed negligible risk of PTHM if utilized as manure. Moreover, significant increment in total N content (3.2-3.8-fold), available P (4-5.9-fold), exchangeable K (3.66-fourfold) and enzyme activity along with significant reduction of TOC (~ 87%) confirmed E. eugeniae and L. mauritii could effectively stabilize MSW. Thus, the metal-binding potential of humic substances produced by earthworms during the detoxification of municipal solid waste (MSW), coupled with a metal budget analysis, has offered valuable insights into the usage of E. eugeniae and L. mauritii as effective contenders for sanitizing heavy metal-laden MSW.

Pivotal role of 99Tc NMR spectroscopy in solid-state and molecular chemistry.

The radioelement Technetium (element 43) pertains to various domains including the nuclear enterprise (i.e., spent nuclear fuel (SNF) reprocessing and nuclear waste remediation) and nuclear medicine (i.e., development of new imaging agents) as well as to the fundamental science of transition metals (i.e., chemical trends in catalytic properties). One method that can provide critical information to improve knowledge in these domains is 99Tc nuclear magnetic resonance (NMR) spectroscopy. The review, presented here, summarizes the pivotal role of 99Tc NMR spectroscopy over the past two decades and presents prospects of the method to tackle challenges in Tc chemistry.

Proof of Concept for the Organic Electrorefinery Technology with Actual Effluents.

This work describes results of a first proof of the concept of electrorefinery with a real waste obtained from a cashew nut factory, and it shows the effect of the current densities of both the anodic oxidation and electrochemically assisted separation processes on the performance of the system. Results obtained demonstrate that electrorefinery is a promising option to minimize the carbon fingerprint, worth studying for increasing the sustainability of the environmental remediation of wastes, because valuable species can be obtained from the destruction of pollutants and recovered within the same integrated process. They also point out that there is still a long way to reach an optimum solution for this technology, but it is worth the effort to be made. Many different carboxylates were detected, but oxalate was the primary product both in the reaction tank and in the recovery tank. The production is almost linear during the electrolysis, with a reaction rate of 23.3 mg C h-1 in the case of oxalate and a separation ration of around 20% in the electrodialysis stage. There is a negligible crossover of aromatic species into the recovery solution, which becomes an important advantage for further processing of the carboxylate solutions in the search to valorize these species in terms of circular economy principles. Energy efficiencies in the range of 0.04-0.21 mg C-carboxylates (Wh)-1 and Coulombic efficiencies in the range 0.92-2.03 mg C-carboxylates (Ah)-1 were obtained in this work. A life cycle assessment indicated carbon dioxide and water footprints as low as 0.31 g of CO2 mg-1 C and 30 mL of H2O mg-1 C recovered in the products obtained, respectively.

Synthesis of nanoporous carbon from Ulva lactuca activated by eggshell for CO2 capture: a novel approach to waste valorization.

Facing the daunting challenge of climate change, driven by escalating greenhouse gas concentrations, our research introduces an innovative solution for CO2 capture. We explore a novel nanoporous carbon derived from Ulva lactuca, activated with eggshell waste, spotlighting waste valorization in mitigating atmospheric CO2. Through a systematic methodology encompassing variable carbonization temperatures (700-900°C) and nitrogen flow rates (2-4ml/min), complemented by a suite of characterization techniques, we unveil the synthesis of this pioneering adsorbent. Our study not only presents a novel, sustainable pathway for CO2 capture but also demonstrates superior performance, particularly with the NC800-4 sample, achieving a CO2 capture capacity of 1.40mmol/g at 30°C, alongside demonstrating consistent adsorption efficiency over four successive adsorption/desorption cycles. This breakthrough underscores the potential of leveraging waste for environmental remediation, offering a dual solution to waste management and carbon capture, utilization, and storage (CCUS) applications.

Remediation of fluoride-contaminated wastes: Chelator-assisted washing and subsequent immobilization using CaO and H3PO4

Fluoride (F) contamination in industrial waste is a significant challenge for sustainable materials recycling. Existing techniques for mitigating F contamination focus on immobilization, converting F compounds to insoluble forms while leaving the total F content untreated. Chelator-assisted washing is considered a promising alternative remediation strategy that can indirectly release F by entrapping and dissolving F-bearing minerals. This study evaluates the effectiveness of chelator-assisted washing in removing F from three real F-contaminated waste samples (TCS-49, TCS-51, and TCS-52) by treating with four different chelators, ethylenediaminetetraacetic acid (EDTA), ethylenediamine N,N′-disuccinic acid (EDDS), diethylenetriaminepentaacetic acid (DTPA), and 3-hydroxy-2,2′-imino disuccinic acid (HIDS). The influence of key washing variables, including chelator type, solution pH, chelator concentration, washing time, and liquid-to-solid (L/S) ratio toward F extraction was assessed and optimized for attaining the maximum extraction. All chelators exhibited the highest F extraction from TCS-49 and TCS-51 at pH 11, whereas in TCS-52 it showed a discrete extraction pattern. Under optimized conditions (concentration, 10 mmol L−1; pH, 11; washing duration, 3 h; and L/S ratio, 10:1), EDTA outperformed the other chelators, enhancing F extraction by 2.1 and 1.2 times for TCS-49 and TCS-51, respectively, compared with those of control treatments. However, for TCS-52, the efficiency of EDTA was analogous to that of the control under the same washing conditions. The linear correlation between the extracted F and F-containing minerals suggests that the chelator-induced F removal from contaminated waste involves the entrapment and dissolution of F-bearing minerals, especially Ca and Fe. The subsequent post-washing immobilization of chelator-washed waste residues using CaO or H3PO4 significantly reduced the content of leachable F under the regulatory limit.

Remediation of plastic waste generated during the COVID-19 pandemic: A conceptual process design of pyrolysis using polyethylene, polypropylene, polystyrene based polymers

During the COVID-19 pandemic, the increase in plastic-based personal protective equipment has raised concerns about managing medical waste and protecting the environment. This study highlights the need for effective waste management strategies by creating a conceptual process flow diagram and investigating thermal treatment methods like pyrolysis as potential solutions. Using computational modeling and process optimization, the study examines different polymer blends, including High-Density Polyethylene (HDPE), Polystyrene (PS), and Polypropylene (PP), to understand how they behave during pyrolysis and the yields they produce. Two pyrolysis schemes have been developed to handle various polymer blends. In Scheme 1, the liquefied polymer is preheated and then pyrolyzed in a reactor, producing a vapor stream and a residue stream (carbon). The vapor stream is cooled to enhance liquid oil production and then is separated in a distillation column to isolate liquid oil from pyrogas. Scheme 2 follows a similar process but converts a significant portion of liquid hydrocarbons to gas in the distillation column, requiring further gas processing in a one-stage separator column. The results show that temperature significantly impacts liquid yield, with specific temperature ranges leading to increased yield. Additionally, the composition of the polymers and the rate at which the material is fed into the process affect the yields, with specific blends showing promise for higher liquid yield. This study emphasizes the importance of accurate process modeling to optimize the operational parameters and improve the economic viability of plastic pyrolysis technology presenting a promising opportunity to convert plastic waste into valuable resources.

Metal oxide-combined sol-gel synthesized ceria nanoparticles: An operative photocatalyst for visible-light-driven mineralization of ciprofloxacin antibiotic in water

The superb spreading of antibiotic waste represents a vital issue related to water and soil contamination that distress the environment and humankind. Accordingly, various research projects for the eco-friendly degradation of such contaminants. Here, we envisioned the coupling of narrow bandgap (Eg) metal oxide with copolymeric-assisted sol-gel-prepared ceria nanoparticles (CeO2) for photoelimination of ciprofloxacin (CiP) as a model for antibiotic waste in water. The few tens nanometer-sized cubic CeO2 was receptive to the irradiated visible light by a combination of a few nanometer-sized AgVO3, Bi2O3, and CoTiO3 at 10.0 wt% by simple precipitation of their salt precursors. The designed nanostructures exposed mesoporous surfaces similar to the pristine CeO2 with a specific surface area range of 165–169 m2 g−1. The 1.25 mg mL−1 dose CoTiO3-composited CeO2 displayed the best-performed photomineralization of CiP (98 ± 1.2 %) within only 2 h of light illumination compared to added oxides with an outstanding reaction rate of 0.0297 min−1. In addition, the CoTiO3/CeO2 displayed a bearable recyclability of five times with 93 % of its mineralization efficiency. The boosted photoactivity of CoTiO3/CeO2 is referred to the momentous light captivation and a band alignment with Eg minimization to 2.48 eV. Also, the constructed heterojunction among n-type CoTiO3 and n-type CeO2 has improved the photoexcited charge separation and migration as resolved by high photocurrent and photoluminescence suppression. Such a comparative study proposes an efficient photocatalyst design for clean and sustainable antibiotic waste remediation.

Evaluation of adsorption isotherms and kinetics of anionic pollutant in water using biochar derived from locally available agro-waste

The uses of agricultural byproduct solid wastes to develop low cost sorbents are advantageous and promising for the removal of water contaminants. It serves the purposes of both environmental remediation and appropriate management of agricultural waste generated during agricultural processing. In this study, locally available apricot seed shell and Salix Alba leaves were utilized as agro-waste for the preparation of adsorbents. The biochar was prepared at 300-370oC via pyrolysis and 80 mesh particle sizes were modified by 1N HCl. The unmodified and acid modified local Salix Alba leaves and Apricot seed shell biochar were used to study the adsorption of chloride ion in water, which can damages appliances of industries and also poses health issues at elevated concentration. Adsorption kinetics and equilibrium studies were conducted at pH 7. The adsorption efficiency of modified biochar was much higher than the unmodified biochar due to induce surface positive charge. The Langmuir maximum adsorption of modified Salix Alba leaves sorbent was found to 22.98 mg/g, while modified Apricot seed shell biochar was found 25.83 mg/g. The experimental data were simulated and applied to fit Langmuir, Freundlich isotherm, pseudo 1st and 2nd order kinetics models and found a better compliance with Freundlich isotherm model and pseudo 2nd order kinetics model.

A synergistic adsorption-catalysis with co-doped Fe/Mn porous PET waste for simultaneous and ambient remediation of hazardous pharmaceutical drugs and dye in multi-component systems by enhancing singlet oxygen

Valorizing single-use plastic waste as an effective activator in environmental protection has gained great interest from policymakers, legislators, and scientific research communities. Herein, low-cost and highly porous alkali Fe/Mn-doped carbon nanomaterials derived from polyethylene terephthalate (PET) waste (MF/cPET-x) were fabricated via facile pyrolysis and alkali-metal impregnation methods. Detailed characterizations of MF-cPET-x demonstrated that the ratio of alkaline impregnation and pyrolysis temperature affects the porous characteristics, content, and size of active sites, specific surface area, and yield of carbon residue/nanocomposite. The main aim of this study was to evaluate and optimize the MF/cPET-x applied for the detoxification of various kinds of pharmaceutical drugs (tetracycline, naproxen, paracetamol, and levofloxacin) and various dyestuff in their single, binary, ternary, and quaternary solutions. The magnetic porous MF/cPET-1 was found to show a most effective PMS activation for single/multiple toxic pollutants removal attaining levels >91.0 % in a wide range of temperatures (5–35 °C) and pH (3.0–9.0), without significant detectable metal leaching (>0.16 mg L−1). The outstanding catalytic performance in complex water environments was mainly attributed to the deposition of Mn/Fe nanoparticles with small grain size on a polymeric scaffold, bimetal synergistic effect, high specific surface area, high stability, and excellent anti-interference capability against coexisting substances. Physicochemical properties of the recycled composite, masking, and EPR analyses confirmed that the dominant reactive species in the following order: 1O2 > OH > SO4− > O2−. This work offers a new and straightforward approach for preparing porous alloy composite from plastic waste for pollutant degradation in various water matrices.

Co-torrefaction and synergistic effect of spent coffee grounds and tea waste for sustainable waste remediation and renewable energy

This study states the enhancement of higher heating value (HHV) by blending spent coffee grounds (SCG) and tea waste (TW) during torrefaction. Torrefied biomass mixture is a carbon-neutral solid biofuel that can be used to replace coal. The synergistic effect ratio (SER) exhibits the synergistic interplay between SCG and TW, consequently elevating HHV and carbon content. Results show that the highest SER occurs at TWS25 (from blending 75 % TW and 25 % SCG is 3.26). Ca contained in TW has the catalytic effect of pyrolyzing the lipid of SCG into higher carbon content in a torrefied solid biofuel mixture, thereby increasing its HHV. The lipid and carbon contents contribute TWS25's HHV by 4.71 % and 95.29 %, respectively. This also illustrated the importance of the carbonization degree during torrefaction to the calorific value of solid biofuel mixture. The XRD, water activity, ATR, contact angle, and mildew observation results indicate that TWS25 has good thermal stability and storage properties. The ignition temperature and combustion reactivity of TWS25 are 325 °C and 3.059 wt%∙min−1∙°C−1, respectively. Overall, the torrefied solid biofuel mixture from blending TW and SCG is a potential biofuel alternative to coal to achieve carbon neutrality, circular bioeconomy, waste remediation, and low carbon initiative.

Exploring the potential of insect gut symbionts for polyethylene biodegradation

The global issue of synthetic plastic pollution is escalating, necessitating innovative bioremediation approaches. Specific insect species have developed symbiotic associations with intestinal microorganisms that possess the ability to degrade resistant plant materials, such as lignocellulose. This is the first study to our knowledge to isolate, characterize, and compare microbial isolates (yeast and bacteria) extracted from the guts of wood-feeding termites (WFT) and lesser waxworms (LWW). The objective was to determine their efficacy in decomposing recalcitrant pollutants, such as low-density polyethylene (LDPE). The isolates belonged to numerous taxonomic groups, as determined by molecular identification; these groups included Bacillus, Citrobacter, Cellulosimicrobium, Rhodococcus, Pseudomonas, Candida, and others. A number of isolates had the potential to degrade LDPE. After 45 days of incubation, the polymer sheets lost 19.8 % of their weight for Bacillus cereus (LDPE-DB2) and 15.4 % of their weight for Candida guilliermondii (LDPE-DY6). Additionally, LDPE degraded by LDPE-DY6 showed a tensile strength loss of 50.3 % compared to that degraded by LDPE-DB2 (58.3 %). During this time, robust biofilm formation was observed on the surfaces of the polymers. Extracellular enzymes such as cutinases, aryl alcohol oxidases, and peroxidases, secreted by specific yeast and bacterial isolates, contribute to the degradation of plastic and recalcitrant biopolymers. Notably, the isolates from LWW demonstrated a greater advantage in this regard than those from WFT. Bacillus cereus, Pseudomonas aeruginosa, Candida guilliermondii, and Sterigmatomyces halophilus were found to have the highest activities in degrading LDPE among the studied WFT and LWW gut-derived symbionts. This study paves the way for a new opportunity to enhance polyethylene degradation by insect gut bacteria and yeasts that may facilitate biotechnological applications for plastic waste remediation.

Characterization of municipal solid waste in Kuwait: Sector-specific composition analysis and implications

ABSTRACT Municipal solid waste (MSW) characterization plays a pivotal role in devising effective waste management strategies conducive to fostering a circular economy. This study presents composition analysis across twenty-four subcategories sourced from residential, commercial, and industrial sectors in Kuwait. The study is conducted in accordance with the Standard Test Method for Determination of the Composition of Unprocessed Municipal Solid Waste (ASTM D5231). The results indicate that organic waste comprises 45.3%, followed by paper waste (19.9%) and plastics (19.8%). The remaining waste comprises glass waste (3.5%), diapers (2.7%), textiles (2.6%) and other waste. Paper waste (19.9%) consists mainly of mixed paper (12.1%), cardboard (3.7%), newspaper (3.3%), printer printouts (0.6%) and other office paper (0.2%). Plastic waste (19.8%) consists mainly of film (11.2%), PET (3.1%), HDPE (1.1%) and other mixed plastics (4.4%). Residential and mixed areas have the highest proportion of organic waste. Commercial areas produce the highest proportion of wastepaper (22.4%) and textiles (3.7%). Industrial areas produce the highest proportion of plastic waste (29.1%), most of which is film (17.3%). The study also provides an overview of the MSW management system in the country, an overview over the legislative framework, and forecasts of future waste generation rates with comparison to historical baselines. Implications: The precise and up-to-date characterization of municipal solid waste is imperative for scholarly journal submissions, as it establishes a foundational understanding of waste composition, aiding researchers and policymakers in the development of effective waste management strategies, resource recovery initiatives, and sustainable solutions to address the evolving challenges in waste management systems. This study provides detailed composition analysis for twenty-four municipal solid waste (MSW) subcategories collected across different sources: residential, commercial, industrial, and mixed areas. Time series forecasting is applied to predict MSW generation based on historical data obtained through the local municipality over the past decade. Factorial analysis is applied to investigate changes across source areas, and a hypothesis test is used to compare the current MSW composition against previous baselines. The results demonstrated significant variation across most waste categories. The plastic waste proportion has increased by 48.5% compared to 2013 data, despite awareness campaigns. Paper waste has also increased in proportion from 6.8% to 16.2%; this increase is associated with the mixed paper subcategory, which is mostly used for packaging. The composition data provided in this study are necessary for long-term monitoring, strategy assessment, and legislation associated with waste reduction and remediation.

Characterization, potential valuable metals recovery and remediation of historic wolframite mining waste

The understanding of tungsten (W) mineral weathering and mobilization in nature remains limited due to W being a transition element with a wide range of oxidation states, which enables it to form a variety of complex chemical compounds. This study examined W mining waste at the abandoned Wolfram Camp mine in North Queensland, Australia, to address this gap. The mineralogical analysis showed the W tailings primarily consisted of silicates, including quartz, illite/mica, plagioclase, and K-Feldspar, with low WO3 content. Static acid mine drainage (AMD) tests indicated most tailings were non-acid forming, while groundwater samples exhibited acidification, with pH ranging from 3.8 to 5.2. The reprocessing trials using gravity separation and bioleaching demonstrated promising results, suggesting both techniques could effectively recover resource and decontaminate the mining waste. The gravity separation reprocessing test has successfully recovered 48.4% W from the tailings, with the resulting W concentrate achieving a 21.6% WO3 grade. On the other hand, the bioleaching reprocessing exhibited a remarkable 44-fold enrichment of W from the tailings, with 2.2% W in the AMD sediment. Synchrotron-based XFM/μ-XANES imaging analysis revealed significant wolframite weathering in reprocessed W concentrates. This study proposed a comprehensive approach, integrating environmental remediation and resource recovery technologies, to repurpose abandoned W mining waste. Passive treatment appears to be an economical option for remediating abandoned W mine sites. The findings provide valuable insights for sustainable W mining waste management and the rehabilitation of the abandoned Wolfram Camp W mine site.

Accelerated de-chelation of EDTA-metal complexes: A novel and versatile approach for wastewater and solid waste remediation

Industrial waste, including wastewater and solid waste, often contains toxic heavy metals that necessitate extraction and separation prior to safe disposal or reusing them. Sewage sludge incineration ash (SSIA), a non-incinerable waste, holds significant amounts of heavy metals such as iron, zinc, copper, nickel, chromium, and lead. Recovery and reuse of heavy metals from SSIA and further application of treated SSIA sludge remain challenging. Ethylenediaminetetraacetic acid (EDTA) is widely used for heavy metals chelation in different applications. While its chelation with heavy metals is rapid and easy to achieve, the de-chelation of the metal complexes is otherwise slow (∼3 days) and challenging due to their high stability constants. In this study, we investigate the recovery of heavy metals from SSIA through chelation using EDTA, and develop, for the first time, a method to rapidly de-chelate the EDTA-metal complexes through the facile chilling process (1 – 3 h) that accelerates the separation of EDTA and metal ions. A sequential precipitation of high-purity heavy metals from the EDTA-metal complexes was demonstrated with and without de-chelation. This novel and versatile method allows the separation of many valuable compounds from the treated SSIA, including regenerated EDTA, potassium hexafluorosilicate, iron phosphate, iron(III) hydroxide, iron silicate, titanium phosphate, calcium phosphate, copper(I) thiocyanate, nickel bis(dimethylglyoximate), lead(II) sulfate, and zinc sulfide. This approach opens doors for more sustainable waste management and the recovery of valuable resources from industrial waste.

Chemical characterization of green liquor dregs from 16 Swedish pulp and paper mills between 2017 and 2019

Green liquor dregs (GLD) is an alkaline by-product from the pulp and paper industry with a pH between 10 and 14. Today most of the produced GLD in Sweden is landfilled. As a fine-grained alkaline material, it might be possible to use it for acid-generating mining waste remediation. To increase the utilization, quality characteristics and environmental performance need to be determined. In this study samples were collected 5 times from 16 mills during a period of 2.5 years, and were characterized by analyzing dry matter content, loss on ignition (LOI) 550 °C and LOI 950 °C, elemental analysis, pH, electrical conductivity, and calorific value. The results were then evaluated using multivariate statistics (PCA) as well as being compared to other studies and Swedish till. The results show that even if GLD is heterogenous (both within a mill and between different mills) trends can be seen for samples from most mills. When samples do stand out, it is predominately related to the same four mills. Most of the studied parameters showed characteristics favorable for use as a remediant; however, TOC, sulfur, and some of the elements require further study. In general, this study concludes that GLD can be a viable option for the remediation of small orphaned sulfidic mining sites and thus worthy of further studies on the interaction between GLD and acidic mining waste.Overall, GLD can be a good alternative for cost-effective remediation of smaller orphaned mining sites. It is readily available in large quantities, has the qualities needed for remediation of many orphaned acidic mining sites, and can often be locally sourced near the mining site. The use of GLD for mining site remediation is likely also a more sustainable method compared to traditional remediation methods.

Mining for Metal-Organic Systems: Chemistry Frontiers of Th-, U-, and Zr-Materials.

The conceptual framework presented in this Perspective overviews the design principles of innovative thorium-based materials that could address urgent needs of the medicinal, nuclear energy, and waste remediation sectors from the lens of zirconium and uranium analogs. We survey the intersections of Zr, Th, and U chemistry with a focus on how the intrinsic behavior of each metal translates to broader material properties, including, but not limited to, structural and topological diversity, preferential metal-ligand binding, and reactivity. On the example of several classes of materials, including organometallic complexes, polyoxometalates, and the primary focus of this Perspective, metal-organic frameworks (MOFs), the design principles that govern the preparation of Zr-, Th-, and U-compounds, including oxophilicity, variation in oxidation states, and stable coordination environments have been considered. Further, we highlight how the impact of the mentioned variables may shift throughout the progression from discrete molecular systems to extended structures. We discuss the common assumption that zirconium-organic materials are typically considered a close analog of thorium-based congeners in areas such as material design and preparation. Through consideration of fundamental chemistry principles, we shed light on the relationships between Zr-, Th-, and U-based materials and highlight how a critical analysis of their distinct properties can be used to target a desired material performance. As a result, we provide a detailed understanding of Th-based materials chemistry by anchoring their fundamental properties between two well-studied reference points, zirconium- and uranium-containing analogs.

Assessment of Innovative Technologies for Hazardous Waste Treatment and Remediation Review: A Sustainable Approach for Environmental Protection

<p>The management of hazardous waste is a critical environmental challenge that requires innovative and sustainable solutions to mitigate adverse impacts on ecosystems and human health. This research project aims to assess and evaluate cutting-edge technologies for the treatment and remediation of hazardous waste, focusing on their sustainability and effectiveness in environmental protection. The study will investigate various innovative methods such as advanced oxidation processes, bioremediation techniques, nanotechnology applications, and green chemistry strategies. These technologies offer promising opportunities to address hazardous waste contamination while minimizing resource consumption and environmental footprints. The research will include a comprehensive review of existing literature, case studies, and technical reports to gather insights into the performance, cost-effectiveness, and environmental benefits of these innovative technologies. Special emphasis will be placed on evaluating their applicability across different types of hazardous waste, ranging from industrial chemicals and pollutants to electronic waste and persistent organic pollutants. Furthermore, the study will analyze regulatory frameworks, policy implications, and socio-economic factors influencing the adoption and implementation of these technologies in diverse industrial sectors and geographical regions. Through rigorous assessment and analysis, this research aims to provide valuable insights and recommendations for stakeholders, policymakers, and environmental practitioners involved in hazardous waste management. The findings will contribute to advancing sustainable approaches for addressing hazardous waste challenges, promoting environmental protection, and fostering a circular economy mindset in waste management practices.</p>

Eco-friendly biomass aerogels from moxibustion waste for sustainable remediation of organic contaminants

Powder adsorbents present limited recyclability when used for wastewater treatment. Bulk materials prepared via eco-friendly approaches typically exhibit excellent reproducibility over powders in terms of removing pollutants from aquatic environments. Here, biomass-based aerogels were synthesized via ball milling a mixture of modified moxa ash (a type of moxibustion waste), carbon nanotubes and ammonia, combined with agarose as biomolecule. The obtained aerogels display low density, high porosity, remarkable mechanical properties, and exceptional repeatability and stability for removing organic pollutants. By employing a two-dimensional (2D) aerogel membrane, pollutants such as 10 mg/L mitoxantrone (MTX), 5 mg/L methylene blue, 5 mg/L malachite green, or 5 mg/L rhodamine B could be dynamically adsorbed and swiftly filtered out, achieving nearly 100 % of the removal rate. For three-dimensional (3D) aerogels, efficient removals of MTX (98.4 % at 135 min) and cationic dyes under various conditions were observed, in which the adsorption capacity reached 28.23 mg/g for low concentration of MTX at 120 min. After four cycles, the aerogel still retained 93 % of its original capacity and the removal rate was still 92.4 %. The adsorption process obeys second-order kinetics and adheres to the Freundlich and Temkin isotherm models. Furthermore, the primary mechanism by which the aerogels adsorb MTX includes pore filling, electrostatic interactions, π-π conjugation and hydrogen bonding. The adsorption mechanism was better explained by the results of density functional theory. Biomass-based 2D/3D aerogels are promising, low-cost, eco-friendly and highly efficient absorbents for mitigating wastewater contamination.

Zinc chloride-assisted activation of açaí biomass for herbicide removal: Insights from adsorption and molecular modeling

In addressing the environmental impact of açaí pulp production waste, this study explores the sustainable transformation of Euterpe oleracea fruit pits into activated carbon using a zinc chloride (ZnCl2) activation process. The primary aim is to repurpose this agricultural by-product for the efficient removal of atrazine (ATZ) and 2,4-dichlorophenoxyacetic acid (2,4-D) herbicides from contaminated water. The produced activated carbon demonstrated superior adsorptive properties, with a specific surface area (SBET) of 920.5 m2 g-1, substantial pore volume (Vp) of 0.467 cm3 g-1, and an average pore diameter (Dp) of 1.126 nm, showcasing its potential as an effective adsorbent. Experimental adsorption tests revealed that this carbonized material could remove up to 95% of ATZ and 89% of 2,4-D under optimized conditions. Advanced techniques, including Density Functional Theory (DFT) simulations and COSMO-RS analysis, provided profound insights into the adsorption mechanisms, particularly emphasizing the crucial role of hydrogen bonding interactions. Identified as key mediators, hydrogen bonding-induced contact energy facilitated herbicide adsorption, corroborated by Electron Localization Function (ELF) analysis. These findings not only suggest a viable method for mitigating the environmental issue posed by açaí pulp waste but also contribute to the development of eco-friendly adsorbents for water purification. The research underscores the potential of using biomass waste for environmental remediation, aligning with global sustainability objectives.