Journal of hazardous materials letters最新文献

The possibility of combined adsorption-degradation processes in wastewater treatment using nanomaterials based on indium sulfide (In₂S₃) is examined in this review paper. Regarding the synergistic adsorption and degradation of pollutants, In₂S₃ performs exceptionally well, making it a suitable choice for wastewater remediation. Insights have been given to the pollutant removal mechanism through this integrated technique. The synergistic removal process is affected by several operational factors, including pH, catalyst dose, pollutant concentration, and contact duration. This analysis highlights the significance of optimizing these parameters for optimal contaminant removal efficiency. The influence of co-existing species, including cations, anions, and organic compounds, on the integrated elimination process is further highlighted by a discussion of their role. Future research directions are suggested, including a better comprehension of underlying processes, investigation of hybrid nanocomposites, and evaluation of long-term stability and recyclability to enhance the applicability of In₂S₃-based nanomaterials. This study aids in the creation of effective and long-lasting wastewater treatment methods by using the potential of In₂S₃-based nanomaterials.

The impact of chain length on the retention and transport of perfluorocarboxylic acids (PFCAs) in a quartz sand was investigated. Short-chain (C4–C7: PFBA, PFPeA, PFHxA, PFHpA) and long-chain (C8–C10: PFOA, PFNA, PFDA) PFCAs were selected as a representative homologous series. Miscible-displacement transport experiments were conducted under saturated conditions to characterize the magnitudes of sorption mediating retention and transport. Quantitative-structure/property-relationship (QSPR) analysis was applied to characterize the influence of molecular size on sorption. The transport of the long-chain PFCAs exhibited greater retardation than the short-chain PFCAs. The log of the equilibrium sorption coefficient (K_d) exhibited a biphasic relationship with carbon number and molar volume, with the magnitude of measured sorption for the short-chain PFCAs significantly greater than would be predicted using the QSPR regression developed for the long-chain PFCAs. This is consistent with batch-measured data reported in the literature, and likely reflects the relative influence of different sorption mechanisms for the short-chain vs long-chain PFCAs.

In this study, we investigated the benefit of combining Chlorella sorokiniana with manganese-containing ferrite nanoparticles (NPs) for heavy metal removal and cell harvesting. Our results demonstrate that the combination of non-toxic nanoparticles significantly enhances the heavy metal removal capacity of C. sorokiniana without affecting its growth. The microalgae combined with NPs was able to sequester Cr⁶⁺, Co²⁺, and Ni²⁺ from aqueous solutions and could remove these metals at a higher adsorption capacity and within a relatively short time than their individual counterparts, indicating a synergistic effect between the algal cells and the nanomaterials, where bioadsorption and chemisorption were the main players. Both biosorption and chemisorption capacities were found to be the highest for single-metal systems and decreased when coexisting ions were present in the solution. The adsorption of the heavy metals evaluated was better described by the pseudo-second order model than the pseudo-first order model, indicating that chemisorption dominated over physisorption. These characteristics suggest that the combination of biosorbents with nanosorbents is a promising approach for the treatment of water contaminated with heavy metals making this process more efficient, economical, sustainable, and clean.

Concerns surrounding potential health and environmental impacts of per- and polyfluoroalkyl substances (PFAS) are growing at tremendous rates because adverse health impacts are expected with trace-level exposures. Extreme measures are required to mitigate potential PFAS contamination and minimize exposures. Extensive PFAS use results in the release of diverse PFAS species from domestic, industrial, and municipal effluents to wastewater, which partition to biosolids throughout secondary treatment. Biosolids generated during municipal wastewater treatment are a major environmental source of PFAS due to prevailing disposal practices as fertilizers. Pyrolysis is emerging as a viable, scalable technology for PFAS removal from biosolids while retaining nutrients and generating renewable, raw materials for energy generation. Despite early successes of pyrolysis in PFAS removal, significant unknowns remain about PFAS and transformation product fates in pyrolysis products and emissions. Applicable PFAS sampling methods, analytical workflows, and removal assessments are currently limited to a subset of high-interest analytes and matrices. Further, analysis of exhaust gases, particulate matter, fly ashes, and other pyrolysis end-products remain largely unreported or limited due to cost and sampling limitations. This paper identifies critical knowledge gaps on the pyrolysis of biosolids that must be addressed to assess the effectiveness of PFAS removal during pyrolysis treatment.

The synergetic and interactive effects of microplastics (MPs) as potential carriers of pollutants and pathogens have a manifold impact on human health and aquatic biota. The present study delineates the role of MPs in transporting heavy metals to the black clam, Villorita cyrpinoides of Vembanad Lake in South India. MPs in water (3.41 ± 1.87 items/L), sediment (154.6 ± 45.4 items/kg) and within clams (0.87 ± 0.34 items/g tissue) showed considerable variation based on their physical and chemical characteristics, which in turn reflected its differential potential to carry heavy metals. Though the levels of heavy metals (Al, Fe, Mn, Zn, Cr, Pb) within the clam and those carried by MPs were less than the hazardous limits, the concentration of Cd within the clam and MP was found to have a positive correlation. Though the present levels of heavy metal pollution in the lake do not pose a direct threat to humans, anthropogenic interventions and reduced water flow have turned the lower reaches of the lake into a sink of heavy metals. Hence with MP concentration increasing it is worth investigating how their future interactions with heavy metals and other pollutants would pose a risk to living organisms.

Background

Increasing use prevalence of waterpipe tobacco products raises concerns about environmental impacts from waterpipe waste disposal. The U.S. Food and Drug Administration (FDA) is required to assess the environmental impact of its tobacco regulatory actions per the National Environmental Policy Act. This study builds on FDA’s efforts characterizing the aquatic toxicity of waterpipe wastewater chemicals.

Methods

We compiled a comprehensive list of waterpipe wastewater chemical concentrations from literature. We then selected chemicals for risk assessment by estimating persistence, bioaccumulation, and aquatic toxicity (PBT) characteristics (U.S. Environmental Protection Agency), and hazardous concentration values (concentration affecting specific proportion of species).

Results

Of 38 chemicals in waterpipe wastewater with concentration data, 20 are listed as harmful or potentially harmful constituents (HPHCs) in tobacco smoke and tobacco products by FDA, and 15 are hazardous waste per U. S. Environmental Protection Agency. Among metals, six (cadmium, chromium, lead, mercury, nickel and selenium) are included in both HPHC and hazardous waste lists and were selected for future risk assessments. Among non-metals, nicotine, and 4-methylnitrosamino-1-(3-pyridyl)− 1-butanone (NNK) were shortlisted, as they are classified as persistent and toxic. Further, N-nitrosonornicotine (NNN), with a low hazardous concentration value (HC₅₀; concentration affecting 50 % of aquatic species) for chronic aquatic toxicity, had high aquatic toxicity concern and is selected.

Conclusions

The presence of multiple hazardous compounds in waterpipe wastewater highlights the importance of awareness on the proper disposal of waterpipe wastewater in residential and retail settings. Future studies can build on the hazard characterization provided in this study through fate and transport modeling, exposure characterization and risk assessments of waterpipe wastewater chemicals.

Titanium dioxide (TiO₂) is a metal oxide that occurs naturally when titanium reacts with airborne oxygen. It has various attractive and beneficial properties, such as thermal stability, photocatalysis potential, and resistance to ultraviolet radiation. As a result, it is widely used in industrial processes and commercial products. The physicochemical properties of TiO₂ can vary depending on the material's primary particle size, crystallinity, and formulation. Different properties have been found to cause different toxicological responses. While most studies have focused on the effects of exposure to nano-TiO₂, little attention has been given to other relevant TiO₂ materials. In this review, we examine the toxicological profile of both titanium dioxide nanoparticles and pigmentary TiO₂. This review aims to provide reliable information on titanium dioxide toxicity for public and private stakeholders to use in risk assessments.

While several sources of per- and polyfluoroalkyl substances (PFAS) are known, their use in consumer household products is far less explored. The aim of this study was to provide comprehensive bottom-up analysis of the types and concentrations of PFAS reported in the literature over the past decade. A total of 52 studies revealed 107 PFAS belonging to 15 different categories in 1040 consumer products. The highest number of products tested were from the USA (n = 389) followed by the Czech Republic (n = 111). Mean PFAS concentrations were highest in household firefighting products, followed by textile finishing agents and household chemicals. The highest diversity of PFAS was reported in textiles (72 PFAS). Fluorotelomer alcohol (FTOH), polyfluoroalkyl phosphate esters (PAPs), perfluorocarboxylic acid (PFCA) and perfluorosulfonic acid (PFSA) are the classes of PFAS of high interest. Eight out of 52 studies used High-Resolution Mass Spectrometry techniques. Highlighted knowledge gaps included (i) the development of analytical methods for detecting a range of PFAS in consumer products, (ii) method validation and QA/QC approaches, (iii) application of suspect and non-target analysis, and (iv) an understanding of human exposure risk. This review highlights that the presence of PFAS in consumer products is of concern and remains underexplored.

Globally, large quantities of oily sludge are produced in petroleum refineries as wastes from petroleum refining processes. Petroleum refinery oily sludge (PROS) is a major by-product of the processes and a major contributor to pollution in the oil and gas industry. In this study, Response Surface Methodology (RSM) was used for optimising and modelling experimental work. Thermally treated PROS replaced fly ash (FA) at 5–20 % in geopolymer mortar mixes at a fixed combination of sodium silicate (Na₂SiO₃) and sodium hydroxide (NaOH). The visual observations and effects of PROS on the density and compressive strength of PROS geopolymer mortar (PGM) were studied. PGM with 10 % replacement of PROS had the maximum compressive strength of 38.17 MPa after 28 days. P-values obtained from the quadratic models developed for the synergistic effect of FA-PROS on density and compressive strength were less than 0.005. Optimisation of the synergistic effect of FA-PROS binder produced an optimal combination of both materials for maximum compressive strength and density of 2200 kg/m³ with desirability factor of 0.981. This investigation shows that replacing PROS with FA in geopolymer mortar can result in a new supply chain for greener binder materials in geopolymer mortar.