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Novel versatile nanomaterials may facilitate strategies for simultaneous soil remediation and agricultural production, but a thorough and mechanistic assessment of efficacy and safety is needed. We have established a new soil remediation strategy using nanoscale zero-valent iron (nZVI) coupled with safe rice production in paddy soil contaminated with pentachlorophenol (PCP). In comparison with rice cultivation in contaminated soil with 100 mg PCP per kg soil but without nZVI, the addition of 100 mg nZVI per kg soil increased grain yield by 47.1–55.0%, decreased grain PCP content by 83.6–86.2% and increased the soil PCP removal rate from 49.9 to 83.9–89.0%. The specific role of nZVI-derived root iron plaque formation in the safe production of rice has been elucidated, and the synergistic effect of nZVI treatment and rice cultivation identified in the nZVI-facilitated rhizosphere microbial degradation of PCP. This work opens a new strategy for the application of nanomaterials in soil remediation that could simultaneously enable safe crop production in contaminated lands. The application of nanoscale zero-valent iron simultaneously increased rice production and rhizoremediation of pentachlorophenol-contaminated soil.

Double-walled metal-organic frameworks (MOFs), synthesized using Zn and Co, are potential porous materials for trace benzene adsorption. Aluminum is with low-toxicity and abundance in nature, in comparison with Zn and Co. Therefore, a double-walled Al-based MOF, named as ZJU-520(Al), with large microporous specific surface area of 2235 m 2  g –1 , pore size distribution in the range of 9.26–12.99 Å and excellent chemical stability, was synthesized. ZJU-520(Al) is consisted by helical chain of AlO 6 clusters and 4,6-Di(4-carboxyphenyl)pyrimidine ligands. Trace benzene adsorption of ZJU-520(Al) is up to 5.98 mmol g –1 at 298 K and P/P 0  = 0.01. Adsorbed benzene molecules are trapped on two types of sites. One (site I) is near the AlO 6 clusters, another (site II) is near the N atom of ligands, using Grand Canonical Monte Carlo simulations. ZJU-520(Al) can effectively separate trace benzene from mixed vapor flow of benzene and cyclohexane, due to the adsorption affinity of benzene higher than that of cyclohexane. Therefore, ZJU-520(Al) is a potential adsorbent for trace benzene adsorption and benzene/cyclohexane separation. Trace benzene poses a risk to the health and safety of humans, resulting in a challenging task. Here authors synthesise double-walled Al-based MOF ZJU-520(Al) with trace benzene adsorption (5.98 mmol g –1 ) and excellent benzene/cyclohexane separation ability.

Controversial and inconsistent results on the eco-toxicity of TiO2 nanoparticles (NPs) are commonly found in recorded studies and more experimental works are therefore warranted to elucidate the nanotoxicity and its underlying precise mechanisms. Toxicities of five types of TiO2 NPs with different particle sizes (10∼50 nm) and crystal phases were investigated using Escherichia coli as a test organism. The effect of water chemistry on the nanotoxicity was also examined. The antibacterial effects of TiO2 NPs as revealed by dose-effect experiments decreased with increasing particle size and rutile content of the TiO2 NPs. More bacteria could survive at higher solution pH (5.0-10.0) and ionic strength (50-200 mg L(-1) NaCl) as affected by the anatase TiO2 NPs. The TiO2 NPs with anatase crystal structure and smaller particle size produced higher content of intracellular reactive oxygen species and malondialdehyde, in line with their greater antibacterial effect. Transmission electron microscopic observations showed the concentration buildup of the anatase TiO2 NPs especially those with smaller particle sizes on the cell surfaces, leading to membrane damage and internalization. These research results will shed new light on the understanding of ecological effects of TiO2 NPs.

Biochar supported nanoscale zero-valent iron (NZVI/BC), prepared commonly by liquid reduction using sodium borohydride (NaBH 4 ), exhibits better reduction performance for contaminants than bare NZVI. The better reducing ability was attributed to attachment of nanoscale zero-valent iron (NZVI) on biochar (BC) surface or into the interior pores of BC particles due to observations by scanning electron microscopy (SEM) and plan transmission electron microscopy (P-TEM) techniques in previous studies. In this study, cross-sectional TEM (C-TEM) technique was employed firstly to explore location of NZVI in NZVI/BC. It was observed that NZVI is isolated from BC particles, but not located on the surface or in the interior pores of BC particles. This observation was also supported by negligible adsorption and precipitation of Fe 2+ /Fe 3+ and iron hydroxides on BC surface or into interior pores of BC particles respectively. Precipitation of Fe 2+ and Fe 3+ , rather than adsorption, is responsible for the removal of Fe 2+ and Fe 3+ by BC. Moreover, precipitates of iron hydroxides cannot be reduced to NZVI by NaBH 4 . In addition to SEM or P-TEM, therefore, C-TEM is a potential technique to characterize the interior morphology of NZVI/BC for better understanding the improved reduction performance of contaminants by NZVI/BC than bare NZVI.

With the fast development of nanotechnology, engineered nanomaterials (ENMs) will inevitably be introduced into the environment. Increasing studies showed the toxicity of various ENMs, which raises concerns over their fate and transport in the environment. This review focuses on advances in the research on environmental transport and fate of ENMs. Aggregation and suspension behaviors of ENMs determining their fate and transport in aqueous environment are discussed, with emphasis on the influencing factors, including natural colloids, natural organic matter, pH, and ionic strength. Studies on the transport of ENMs in porous media and its influencing factors are reviewed, and transformation and organism cleansing, as two fate routes of ENMs in the environment, are addressed. Future research directions and outlook in the environmental transport and fate of ENMs are also presented.

Biochar (BC) colloids attract increasing interest due to their unique environmental behavior and potential risks. However, the interaction between BC colloids and organic contaminants that may affect their fates in the environment has not been substantially studied. Herein, adsorption and desorption of phenanthrene (PHN), atrazine (ATZ), and oxytetracycline (OTC) by a series of BC colloids derived from bulk rice straw BC samples with 6 pyrolysis temperatures (200–700 °C), and 3 particle sizes (250 nm, 500 nm, and 1 μm) were investigated. Regardless of pyrolysis temperature, BC colloids from a given sized bulk BC had a comparable size, being 30 ± 6, 70 ± 18, and 140 ± 15 nm corresponding to the three sized bulk BCs, respectively. The adsorption kinetics curves were well explained by the pseudo-second-order model, and pore diffusion was the primary rate-determining step. Both Freundlich and Langmuir models well fitted the adsorption isotherms. With increasing pyrolysis temperature or decreasing particle size of bulk BC, the specific surface area and pore volumes of the derived BC colloids increased, the kinetics model fitted adsorption rates ( k 2 ) of the three organics by the BC colloids all largely decreased, and the Langmuir model fitted adsorption capacities ( Q max ) increased. The highest Q max was obtained by BC colloids from the smallest (250 nm) bulk BC with the highest pyrolysis temperature (700 °C), being 212 μmol g −1 for PHN, 815 μmol g −1 for ATZ, and 72.4 μmol g −1 for OTC. The adsorption was reversible for PHN and ATZ, while significant desorption hysteresis was observed for OTC on BC colloids with middle pyrolysis temperatures (300–500 °C). The underlying mechanisms including hydrophobic interaction, π–π electron donor-acceptor interaction, molecular size effect, and irreversible reactions were discussed to explain the difference in the adsorption and desorption behaviors. The findings increased our understanding of the environmental fate and risk of BC.

In this study, we observed that four congeners, including naphthalene (Nap), acenaphthylene (Acy), phenanthrene (Phe), and benz(a)anthracene (BaA), are the characteristic congeners for predicting the emission and the sediment concentrations of polycyclic aromatic hydrocarbons (PAHs). A novel multiple relationship of the total PAHs concentrations (C ∑PAHs ) in sediments with the concentrations of four congeners was established ( p  < 0.01, R 2  = 0.95) using published data over the past 30 years. Moreover, the multiple linear relationship of the total PAHs emission factors with the emission factors of four congeners was also established ( p  < 0.01, R 2  = 0.99). Interestingly, the ratio of multicomponents coefficient from the multiple linear relationship in sediments to that from the multiple linear relationship in emission sources correlated positively with octanol–water partition coefficient (log K ow ) ( p  < 0.01, R 2  = 0.88) of the four PAHs congeners. Therefore, a novel model was established to predict C ΣPAHs in sediments using the emissions and log K ow of the four characteristic PAHs congeners. The percent sample deviation between calculated C ∑PAHs and their observed values was 54%, suggesting the established model can accurately predict C ΣPAHs in sediments.

Co-transport of biochar (BC) colloids with coexisting organic contaminants (OCs) in soil involves complex interactions among BC colloids, OCs, and soil particles, which is significant for the environmental application and risk assessment of BC and yet has not been well addressed. This study explored co-transports of three typical OCs (i.e., phenanthrene (PHN), atrazine (ATZ), and oxytetracycline (OTC)) and BC colloids obtained from bulk BCs with different charring temperatures (200–700 °C) and particle sizes (250 nm, 500 nm, and 1 μm) in a soil column of 9 cm in height. Considerable transport of BC colloids alone was observed and the maximum breakthrough concentration ( C / C o ) increased from 0.08 to 0.77 as the charring temperature decreased from 700 to 200 °C. The mobilities of PHN, OTC, and ATZ alone were very low but were greatly increased by co-transports with BC colloids, and their maximum C/C o values were within 0.05–0.33, 0.03–0.44, and 0.05–0.62, respectively, in the absence and presence of various BC colloids. The enhancement effect of BC colloids on the OC transport decreased with increasing charring temperature or particle size of BC colloids. BC colloids mainly acted as a vehicle to facilitate the transport of OCs, and dissolved organic carbon from BC colloids also contributed to the increased mobility of OCs in dissolved form. These findings provide new insights into co-transport of BC colloids and contaminants in soil.

High-valent iron-oxo species (Fe IV =O) have garnered increasing attention for water purification, while the selective generation of Fe IV  = O in Fenton-like reactions still lacks an effective control protocol at the atomic level. Here, we propose an innovative coordination strategy to develop a series of diatomic FeM p –N–C catalysts with p-block metals (M p : Bi, In, and Sb) for improving the selectivity of Fe IV  = O generation via peroxymonosulfate (PMS) activation. The p-block metal coordination facilitates the chemical bonding with the terminal hydroxyl oxygen of PMS to construct an electron-rich microenvironment surrounding the Fe active center, thereby transferring twice as many electrons to enable Fe IV  = O production through the high-spin-state Fe III intermediates. Consequently, the steady-state concentrations of Fe IV  = O in FeM p –N–C/PMS systems are substantially enhanced by almost an order of magnitude compared to conventional Fe–N–C and state-of-the-art FeM d –N–C catalysts (M d : Cu, Mn, and Ni). Under p-block metal coordination, FeM p –N–C catalysts selectively shift the Fe–N–C-PMS * complex-mediated electron transfer regime into the Fe IV  = O-dominated oxidation process, ultimately accounting for the efficient and sustainable degradation of organic pollutants. Our findings demonstrate a fundamental breakthrough in atomic-level electronic engineering for the selective synthesis of Fe IV  = O, which will provide promising prospects for environmental remediation and other catalytic applications. This study proposes a p-block metal coordination strategy to engineer the single-atom Fe sites for improving the selectivity of Fe IV  = O generation in peroxymonosulfate (PMS)-based Fenton-like reactions

The water evaporation rate of 3D solar evaporator heavily relies on the water transport height of the evaporator. In this work, a 3D solar evaporator featuring a soil capillary‐like structure is designed by surface coating native balsa wood using potassium hydroxide activated carbon (KAC). This KAC‐coated wood evaporator can transport water up to 32 cm, surpassing that of native wood by ≈8 times. Moreover, under 1 kW m−2 solar radiation without wind, the KAC‐coated wood evaporator exhibits a remarkable water evaporation rate of 25.3 kg m−2 h−1, ranking among the highest compared with other reported evaporators. The exceptional water transport capabilities of the KAC‐coated wood should be attributed to the black and hydrophilic KAC film, which creates a porous network resembling a soil capillary structure to facilitate efficient water transport. In the porous network of coated KAC film, the small internal pores play a pivotal role in achieving rapid capillary condensation, while the larger interstitial channels store condensed water, further promoting water transport up more and micropore capillary condensation. Moreover, this innovative design demonstrates efficacy in retarding phenol from wastewater through absorption onto the coated KAC film, thus presenting a new avenue for high‐efficiency clean water production. A novel 3D solar evaporator featuring a soil capillary‐like structure is prepared by coating native balsa wood using KOH activated carbon (KAC) to address the issue of limited energy and rate efficacy for traditional 3D solar evaporator. This coating structure enables a remarkable capillary water transport height of 32 cm and a peak water evaporation rate of 25.3 kg m−2 h−1 under similar solar radiation conditions without wind.