Carbon nanotubes (CNTs) and their derivatives have been widely exploited to activate various oxidants for environmental remediation. However, the intrinsic mechanism of CNTs-driven periodate (PI) activation remains ambiguous, which significantly impedes their scientific progress toward practical application. Here, we found that CNTs can strongly boost PI activation for the oxidation of various phenols. Reactive oxygen species analysis, in situ Raman characterization, galvanic oxidation process experiments, and electrochemical tests revealed that CNTs could activate PI to form high-potential metastable intermediates (CNTs–PI*) rather than produce free radicals and 1O2, thereby facilitating direct electron transfer from the pollutants to PI. Additionally, we analyzed quantitative structure–activity relationships between rate constants of phenols oxidation and double descriptors (e.g., Hammett constants and logarithm of the octanol–water partition coefficient). The adsorption of phenols on CNT surfaces and their electronic properties are critical factors affecting the oxidation process. Besides, in the CNTs/PI system, phenol adsorbed the CNT surfaces was oxidized by the CNTs–PI* complexes, and products were mainly generated via the coupling reaction of phenoxyl radical. Most of the products adsorbed and accumulated on the CNT surfaces realized phenol removal from the bulk solution. Such a unique non-mineralization removal process achieved an extremely high apparent electron utilization efficiency of 378%. The activity evaluation and theoretical calculations of CNT derivatives confirmed that the carbonyl/ketonic functional groups and double-vacancy defects of the CNTs were the primary active sites, where high-oxidation-potential CNTs–PI* were formed. Further, the PI species could achieve a stoichiometric decomposition into iodate, a safe sink of iodine species, without the generation of typical iodinated byproducts. Our discovery provides new mechanistic insight into CNTs-driven PI activation for the green future of environmental remediation.
A Co3O4-activated chlorite (Co3O4/chlorite) process was developed to enable the simultaneous generation of high-valent cobalt species [Co(IV)] and ClO2 for efficient oxidation of organic contaminants. The formation of Co(IV) in the Co3O4/chlorite process was demonstrated through phenylmethyl sulfoxide (PMSO) probe and 18O-isotope-labeling tests. Both experiments and theoretical calculations revealed that chlorite activation involved oxygen atom transfer (OAT) during Co(IV) formation and proton-coupled electron transfer (PCET) in the Co(IV)-mediated ClO2 generation. Protons not only promoted the generation of Co(IV) and ClO2 by lowering the energy barrier but also strengthened the resistance of the Co3O4/chlorite process to coexisting anions, which we termed a proton enhancement effect. Although both Co(IV) and ClO2 exhibited direct oxidation of contaminants, their contributions varied with pH changes. When pH increased from 3 to 5, the deprotonation of contaminants facilitated the electrophilic attack of ClO2, while as pH increased from 5 to 8, Co(IV) gradually became the main contributor to contaminant degradation owing to its higher stability than ClO2. Moreover, ClO2– was transformed into nontoxic Cl– rather than ClO3– after the reaction, thus greatly reducing possible environmental risks. This work described a Co(IV)-involved chlorite activation process for efficient removal of organic contaminants, and a proton enhancement mechanism was revealed.
Peroxy radicals (RO2), which are formed during the oxidation of volatile organic compounds, play an important role in atmospheric oxidation reactions. Therefore, the measurement of RO2, especially distinct species of RO2 radicals, is important and greatly helps the exploration of atmospheric chemistry mechanisms. Although the speciated detection of RO2 radicals remains challenging, various methods have been developed to study them in detail. These methods can be divided into spectroscopy and mass spectrometry technologies. The spectroscopy methods contain laser-induced fluorescence (LIF), UV-absorption spectroscopy, cavity ring-down spectroscopy (CRDS) and matrix isolation and electron spin resonance (MIESR). The mass spectrometry methods contain chemical ionization atmospheric pressure interface time-of-flight mass spectrometry (CI-APi-TOF), chemical ionization mass spectrometry (CIMS), CI-Orbitrap-MS and the third-generation proton transfer reaction–time-of-flight mass spectrometer (PTR3). This article reviews technologies for the speciated detection of RO2 radicals and the applications of these methods. In addition, a comparison of these techniques and the reaction mechanisms of some key species are discussed. Finally, possible gaps are proposed that could be filled by future research into speciated RO2 radicals.
More than three decades after the release of his seminal work An Age in Motion: Popular Radicalism in Java, 1912–1926, Takashi Shiraishi finally published the long-awaited sequel, The Phantom World of Digul. Initially conceived with the self-explanatory title An Age of Normalcy, the monograph draws a sharp contrast with its prequel by investigating the interplay of the colonial regime’s political policing and the concurrent nationalist movement in the final years of the Dutch East Indies. While scholars commonly see the late 1920s and 1930s as a period of “peace and order” under the relatively stable rule of the Dutch Beambtenstaat—an “apolitical, administrative polity par excellence,” Shiraishi demonstrates that the colonial authority achieved such “normalcy” by “reducing the problem of nationalism to the question of police” (p. 16). Boven Digul, a remote penal colony established to intern recalcitrant communists and radical nationalists, stood out as a jarring antithesis to such “normalcy.” The mass internment camp served as both a metaphor and ground for the colonial regime’s policing and surveillance practices, epitomizing Dutch repressive colonial strategies that aimed to confine Indonesians’ political life within an extremely narrow space.
The Archaeology of Roman Macedonia: Urban and Rural Environments by Vassilis Evangelidis offers “a synthetic look at the built environment [of Roman Macedonia],” or “all [its] built features that constitute the human habitus: buildings, monuments and spaces created or modified by people” (p. 41). Evangelidis specifically states that the book is “meant to provide a starting point for those who want to delve deeper into more specialized subjects” (p. 195). Evangelidis is an organizer of the Roman Seminar, which offers lecture series that discuss new archaeological discoveries and studies pertaining to Roman Greece. Evangelidis’ book can be seen as an addition to this effort but with more focus on recent and ongoing systematic and rescue excavations in northern Greece, Albania, North Macedonia, and Bulgaria.[1] The book is in three parts. Part I provides contextual information on how ancient Macedonia transitioned from the old Macedonian kingdom to the imperial period. Evangelidis takes particular interest in: 1) the breaks and continuities in demography, ethnic makeup, social stratification, cult practice, and civic institutions following the demise of the Macedonian kingdom; and 2) the removal and exodus of the Macedonian elites and the repopulation of Macedonia by persons, groups, and agencies from different regions of the Mediterranean world. The map in chapter three (p. 26, fig. 4) captioned “the urban network: old and new cities” offers an intriguing bird’s-eye view of two Macedonias: the old Greek coastal cities, such as Maroneia and Abdera, in decline, while the accumulation of roads brought about new connectivity with significant impact on the interior as the main economic interest shifted away from the coast and towards inland areas where new cities were founded, such as Traianopolis and Ulpia Tpeiros (p. 37). The synthetic view becomes kaleidoscopic in Part II. Built features are classified according to public, commercial, industrial, ritual, entertainment, and other such types. Individual chapters focus on a single category of building types supported by layouts, stylistic features, functions, comparanda. Guiding themes and problems are given, at times subtly. On Public spaces (agorai/fora), for instance, Evangelidis invokes questions of how or whether they were transformed from Macedonian precursors or built anew, since there were scant remains of pre-Roman built features (ch. 5). Individual public and administrative buildings (ch. 7) and buildings for commerce and industry (ch. 8) follow, with attention directed towards the difficulty of function-based identifications (e.g., p. 59-60: what was the Building with the Arches at Stobi?). On ritual space (ch. 9), descriptions (e.g., Pseudo-Lucian’s highly relevant Lucius or Ass), as well as inscriptions concerning rituals, festivities, and cult worship, are anecdotal evidence useful for envisioning a populated, dynamic, and eclectic built environment at a specific point in time, but how can such sources fit into interpretations of continuity, adaptation, or the eclecticism of temples and sanctuaries? Surveys and discussion of the architecture of entertainment (ch. 10) also rely on similar issues, particularly on what traditional entertainment spaces actually were transformed into dual-use venues to accommodate a thriving gladiator culture from the second century CE onwards. The chapter on “the architecture of water” covers a dazzling array of the numerous aqueducts, latrines, fountains, and baths built during the Roman period (ch. 11). The natural abundance of water in Macedonia and the early developments of the Hellenistic balaneia(e.g., in Thessaloniki and Pella, pp. 108-109, and Amphipolis, pp. 114-115) may be taken as the driver for Macedonia’s “culture of water” that extended even to the most rural parts within the province. On built features of movement and passage (ch. 12), Evangelidis suggests the term “urban armatures” (p. 121). Many of these built features speak to the architectural language of imperial Rome, and Evangelidis suggests that they were purposely used to “hierarchize” urban spaces and regulated access, movement, and behavior (p. 128). One wonders to what degree the impact of hierarchized or regulated spaces are archaeologically visible. For “housing in urban and peri-urban contexts” (ch. 13), Evangelidis notes beyond traditional oikia houses and Roman style atria houses there was also the fusion type called the “courtyard house” that had various spaces opening around one or more courtyards (pp. 131-132). But non-elite domestic architecture remains poorly attested and understood (p. 141). Chapter 14 discusses architecture of defense. It is noteworthy that so little effort was made to build or at least reinforce urban defense against known and repeated northern incursions from the mid-second century onwards; Evangelidis suggests that hillside forts and fortified villas on highlands, including the rough stones crowning hill tops in Aegean Thrace, may have been local solutions to threats. In addition to built features commonly seen in other Balkan provinces (e.g. funerary altars, sarcophagi), “Deathscapes” (ch. 15) discusses hundreds of third-century CE vaulted tombs typical of elite burial in earlier Macedonian kingdom, but to what degree can they be seen as “the mimicking of past funerary architecture” and part of a trend to revive the glorious Macedonian past (p. 156)? The last chapter (ch. 16) of Part II, which covers rural sites, raises questions regarding the differentiation of villas from farmsteads, and the dangers of classifying sites into types such as farms, villages, hamlets, and roadside settlements. Much appreciated is Evangelidis’ discussion of how rural sites may be connected to land and maritime transport networks, and figure 37 (p. 161) offers good visual guidance on the patterns of association between these two facets of Roman Macedonia. Part III is comprised of four (again compact) chapters in which Evangelidis argues that Roman Macedonia should not be perceived exclusively in “Roman” terms. The chapter on the course of development of urban environments (ch. 18) identifies two phases of architectural development. The first is the Late Hellenistic to Early Roman, when materials were local and types mostly Hellenistic in character (p. 176-178) . The second phase is from the mid-2nd century to the early 4th century CE, when major urban spaces underwent rapid and comprehensive convergence with empire-wide social and cultural trends, and adapted existing public and private spaces to contemporary architectural and spatial models (pp. 177-178). But, as Evangelidis keeps reminding readers, the survival of local styles of construction, the reuse of building materials, maintenance, modification, and adaptation of pre-existing buildings complicate chronologies (pp. 176-177). Colonies may have earlier stages of built features by the first Italian colonists, then later reconfigurations (basically the levelling/erasure of pre-existing structures) create new, “coherent,” and even “theatrical” urban landscapes (p. 183). Roman Macedonia was also receptive to a broad range of spatial and architectural ideas (p. 185). Intra-city rivalries and euergetism can lead to unconventional forms of monumentaliztion (p. 186). For rural environments (ch. 19) Evangelidis is mostly concerned with the theory that (or rather the question whether) “Roman Macedonia was systematically and intensively exploited through a dense network of large and medium-sized estates” (p. 188). Evangelidis argues that, while the villa economy model may be useful, there is also evidence (e.g., the farm at Toumba outside Thessaloniki, the site in Aphytis, and the cluster of farms in Lete) that suggest villa-centric interpretations have limitations (p. 188). The many ritual sites (e.g., Hero Equitans, sanctuaries of Zeus Hypsistos, the sanctuary of Ennodia in Kozani), burial tumuli (e.g., Gomati cemetary in Chalkidike), and dispersed native settlements (along the Rodope mountains) did not conform to a “rational” Romanized landscape characterized by organized agricultural activities and a villa-centered lifestyle, and could achieve centrality through centuries’ of evolving perceptions about space and occupation of land in their immediate locales (pp. 191-192). The last chapter of the book (ch. 20) compares Roman Macedonia with Roman Achaea. Evangelidis wishes to push back against an “archaeological orthodoxy” that sees little architectural difference between the two. But he does not explicate how they were different, except a matter-of-fact statement: “clearly, for many small cities and towns in Macedonia—especially the ones away from the coast like Vardarski rid (Gortynia?), Eidomene, Styberra or Petres—the experience of urban living and the form of the built environment was different than the one in Achaea” (p. 193). But the sole discussion on Vardarski rid, which also covers Petres in Florina, offers only a short comment on domestic architecture, that it must have been the “simple compact house…with no central colonnaded court,” a potential local variant of “the Greek courtyard house” that was “better suited to the colder weather conditions” (p. 129). For Eidomene, the discussion focuses on the Roman-style podium temple” found there, a typical frontal temple of Italy, prostyle and standing on a podium, donated by a makedoniarch (p. 79). Would this experience be entirely alien from, say, Patras, Corinth, or even Athens in Roman Achaea? Chapter 17, “Building methods and construction techniques” centers on the systematic use of cement, particularly the opus mixtum technique, or “bricks laid in bands alternating with course of rubble covered with binding material” (p. 173) distinct from the opus caementicium technique (p. 174, fig. 39), as the photos helpfully illustrate. One also appreciates the reminder that the “exclusively brick” opus caementicium technique was closely associated with the introduction of imperially-controlled figlinae in the Tetrachic period, and it is seen not only at the Galerian complex but also in domestic complexes in Thessaloniki, Dion, and Stobi (pp. 174-175). Diligent readers might find it unfortunate that specific types of vaulting and vaulted spaces (e.g. “barrel-vaulted,” p. 47, 72; “radial vaults,” p. 98; “wedge-shaped” vaults, p. 101; “pitched-brick” vaulting [the earliest known Roman example!], p. 105) mentioned throughout the book received no treatment in this chapter, which would have been a contribution, considering that Lynne Lancaster’s Innovative Vaulting in the Architecture of the Roman Empire: 1st to 4th Centuries CE(2015) does not cover most of the examples that Evangelidis mentions.[2] Some readers might appreciate an index, considering that sites mentioned in the book are numerous and cross multiple countries. Site summaries (including site-specific introductions, maps and site plans, and bibliography, as seen in John Camp’s Archaeology of Athens, pp. 247-327) would have been very useful. But for a survey aiming to provide “a starting point for those who want to delve deeper,” some sort of general map with a full list of sites mentioned in the text (e.g., Susan Alcock’s Graecia Capta, pp. 10-12) would have been useful. One might also wish for more site plans, photos, and maps. There seems to be potential to create a supplementary digital humanities project comparable to the beautiful and informative Gardens of the Roman Empire Project, originally modeled on Gardens of Pompeii (1979-1993), that complements the edited volume Gardens of the Roman Empire (2018). To sum up, there is much to like about this book. Evangelidis strings together the full spectrum of architectural features within a large “built environment,” and creates useful syntheses of new and ongoing archaeological work in northern Greece and elsewhere. Readers interested in Roman archaeology in general may benefit from the comparanda described and analyzed, thanks to Evangelidis’ coherent narration and analysis, and perhaps his up-to-date bibliography. Students may particularly benefit if a potential online edition can bring together visual aids and other resources currently not part of the printed edition. Notes [1] Though not entirely exhaustive: Heraclea Sintike (with its well-excavated Hellenistic agora/Roman forum) is not mentioned, for example. Cf. L. Vagalinski, “Heraclea Sintica and Some of Its Recently Found Marble Sculptures,” Archaeologica Bulgarica 24.2 (2020) 1-39; N. Sharankov, “Five Official Inscriptions from Heraclea Sintica Including a Record of the Complete Cursus Honorum of D. Terentius Gentianus,” Archaeologia Bulgarica 25.3 (2021) 1-43. [2] The odeion at Thessaloniki, p. 60; Arch of Galerius, p. 63; Rotunda of Galerius, p. 89.
Exhibiting as a combination of viscous, elastic, and plastic behavior, rheology is a branch of physics and is majorly concerned with continuum mechanics for flow characterizations, particularly non-Newtonian flow like foam. However, most existing studies of foam rheology are primarily focused on water-based foam, while oil-based foam rheology lacks adequate understanding, plus few comprehensive experimental analyses have been done. This study, for the first time, investigates the rheological behavior of oil-based nitrogen foam with full foam quality and shallow reservoir conditions through a newly-designed visualized capillary rheometer. Basically, the effects of foam quality and shear rate on foam morphology and apparent viscosity were elucidated, and the foam rheology at different temperatures and pressures was evaluated. More specifically, with increasing shear rate, the apparent viscosity of nitrogen foam decreases in a concave-down parabola pattern. With the foam quality of 86 %, the apparent viscosity of the foam flow is found to reach its maximum value, 58.4 mPa·s, at the flow rate of 4 mL/min, temperature of 25 °C and pressure of 5 MPa. The foam flow gradually becomes uniform and dense and the apparent viscosity elevates with increasing foam quality up to 86 %. After that, the foam flow tends to be slug flow and its stability becomes worse with linearly-decreasing apparent viscosity. With increasing pressure, the apparent viscosity and consistency coefficient increase, which result in the increase of rheological index and decrease of non-Newtonian property. The temperature effects on the foam flow are absolutely opposite but stronger in comparison to pressure effects as aforementioned. In addition, the rheological equations of nitrogen foam are determined by fitting the consistency coefficient and rheological index with foam quality. Overall, thorough investigations of the rheology of oil-based nitrogen foam would be of great importance for foam theory and practice.
Antibiotics are emerging pollutants that have detrimental effects on both target and non-target organisms in the environment. However, current methods for environmental risk assessment primarily focus on the risk to non-target organisms in ecosystems, overlooking a crucial risk of antibiotics - the induction of resistance in targeted bacteria. To address this oversight, we have incorporated resistance (R) risk with persistence, bioaccumulation and toxicity (PBT) to establish a more comprehensive PBTR (persistence, bioaccumulation, toxicity, and resistance) framework for antibiotic-specific risk assessment. Using the PBTR framework, we evaluated 74 antibiotics detected in Chinese seawater from 2000 to 2021, and identified priority antibiotics. Our analysis revealed that the priority antibiotics with R risk accounted for the largest proportion (50% to 70%), followed by P risk (40% to 58%), T risk (16% to 35%) and B risk (0 to 13%). To further categorize these priority antibiotics, we assigned them a risk level according to their fulfillment of criteria related to P, B, T, and R. Antibiotics meeting all four indicators were classified as Grade I, representing the highest risk level. Grade II and Grade III were assigned to antibiotics meeting three or two indicators, respectively. Antibiotics meeting only one indicator were classified as Grade IV, representing the lowest risk level. The majority of priority antibiotics fell into Grade IV, indicating low risk (55% to 79%), followed by Grade III (16% to 45%). The highest risk antibiotic identified in this study was clindamycin (CLIN), categorized as Grade II, in the East China Sea. Our findings aligned with previous studies for 25 antibiotics, affirming the validity of the PBTR framework. Moreover, we identified 13 new priority antibiotics, highlighting the advancement of this approach. This study provides a feasible screening strategy and monitoring recommendations for priority antibiotics in Chinese seawater.
Abstract Different adverse health effects of submicron (PM1) and fine particles (PM2.5) may be attributed to their chemical differences, requiring a better understanding of size-resolved composition. Herein, extensive online measurements were conducted across seasons in Beijing by two aerosol mass spectrometers, one of which alternately sampled PM1 and PM2.5. Source apportionment of organic aerosol (OA) indicated that traffic- and cooking-related OA together accounted for ∼20%−30% of the OA mass in PM2.5, showing insignificant seasonal variations. Coal-combustion and biomass-burning-related OA had minor contributions. The two secondary OA (SOA) factors together accounted for 59%−73% of the OA mass in PM2.5. The mass distributions of particulate components in PM1 and PM2.5 varied greatly across seasons. Secondary formation played a key role in particle size growth during cold seasons. During severe hazes with high aerosol liquid water content (ALWC), the supermicron mass fraction (MF1−2.5) of secondary components reached ∼40%−50% while those for primary OA remained at ∼20%. Heterogeneous uptake, aqueous processing, and dissolution likely all contributed to the enhanced concentration of secondary components, and the former two were perhaps more important. The increase of MF1−2.5 for secondary components with increasing ALWC in spring was less than that in winter, possibly due to the shorter duration of stagnant conditions limiting secondary formation. Early autumn showed higher MF1−2.5 values than cold seasons with insignificant changes as ALWC varied, plausibly explained by intensive new particle formation hindering persistent particle growth. Our results highlight the importance of heterogeneous uptake and aqueous processing in distributing SOA in supermicron mode in polluted areas.
Semiconducting minerals (such as iron sulfides) are highly abundant in surface water, but their influences on the natural photochemical process of contaminants are still unknown. By simulating the natural water environment under solar irradiation, this work comprehensively investigated the photochemical processes of anthracene (a typical Polycyclic Aromatic Hydrocarbons) in both freshwater and seawater. The results show that the natural pyrite (NP) significantly promotes the degradation of anthracene under solar illumination via 1) NP induced photocatalytic degradation of anthracene, and 2) Fenton reaction due to the NP induced photocatalytic generation of H2O2. The material characterization and theoretical calculation reveal that the natural impurity in NP enlarges its band gap, which limits the utilization of solar spectra to shorter wavelength. The contribution of generated reactive intermediates on anthracene degradation follows the order of 1O2 > OH > O2− in freshwater and O2− > 1O2 > OH in seawater. The photochemically generated H2O2 is a vital source for OH generation (from Fenton reaction). The steady-state concentration of OH, 1O2 and O2− in freshwater were monitored as 3.0 × 10−15 M, 1.1 × 10−13 M, and 4.5 × 10−14 M, respectively. However, the OH concentration in seawater can be negligible due to the quenching effects by halides, and the 1O2 and O2− concentrations are higher than that in freshwater. An anthracene degradation kinetic model was built based on the experimentally determined reactive intermediates concentration and its second order rate constant with anthracene. Moreover, the anthracene degradation pathway was proposed based on intermediates analysis and DFT calculation, and its toxicity evolution during the photochemical process was assessed by quantitative structure-activity relationship (QSAR) based prediction. This finding suggests that the natural semiconducting minerals can affect the fate and environmental risks of contaminants in natural water.