Nanoconfinement engineering for enchanced adsorption of carbon materials,metal–organic frameworks,mesoporous silica,MXenes and porous organic polymers: a review

In material synthesis, nanoconfinement acts both as a physical reactor to tune the shape and size of nanomaterials, and as a chemical microenvironment for the nucleation and growth of nanoconfined substances, resulting in unique material properties. This nanoconfinement effect has been extensively applied to synthesize materials for hydrogen storage, catalysis and separation for environmental protection. Here, we review methods to construct nanoconfined space in carbon materials, metal–organic frameworks, mesoporous silica, porous organic polymers and MXenes, a class of two-dimensional inorganic compounds. We discuss nanoconfinement for enhanced adsorption with focus on covering size and dispersion, crystallization and stability, confined water and coordination.

     

Irrigation suitability of White River in Indiana,Midwestern USA

Climate change models consistently project future precipitation reduction and temperature increase during the crop growing season in the US Midwest, which may exacerbate surface water scarcity issues confronting regional agriculture. To maintain consistent crop yields under the risk of increased droughts, farmers may shift from rain-fed agriculture to irrigation agriculture, particularly during drought periods. There is an urgent need to understand whether surface water in the Midwest is suitable for irrigation. In this study, irrigation water quality was comprehensively analyzed for commonly used parameters regarding salt content including sodium adsorption ratio (SAR), adjusted sodium adsorption ratio (SAR_adj), soluble sodium percentage (SSP), electrical conductivity (EC), total dissolved solids (TDS), residual sodium bicarbonate (RSBC), magnesium adsorption ratio (MAR), permeability index (PI), Kelley’s ratio (KR), synthetic harmful coefficient (SHC), and salinity. Results indicate that water in the White River at Muncie was rated mostly in excellent to good condition with regard to irrigation quality. However, the irrigation suitability level exhibited two distinct patterns between May–July and August–October. Specifically, an average of 7.8% of the samples from May to July were unsuitable for irrigation, and an average of 24.5% of samples from August to October were unsuitable for irrigation considering all parameters. Flow rate change over time and the release of pollutants from wastewater treatment plants and combine sewage outflows to the White River impacted on the irrigation water quality variations of the river. This study showed that there are higher risks during the fall season for farmers to use surface water as an irrigation source, and this risk might be greater if extended or more frequent drought events occur in the future. To our best knowledge, this is the first peer-reviewed study on irrigation water quality assessment in the Midwest and provides useful information for farmers and decision makers to consider while formulating applications for irrigation.

     

Chemistry,abundance, detection and treatment of per- and polyfluoroalkyl substances in water: a review

Per- and polyfluoroalkyl substances (PFAS) encompass a wide range of compounds containing carbon–fluorine bonds. Due the strength of this bond and the high electronegativity of fluorine atoms, PFAS display stability, wettability and other characteristics that are unique for industrial applications and products. However, PFAS induce adverse effects on the environment and human health. Here we review the chemistry, synthesis, properties, analysis, occurrence in water, filtration, removal and oxydation of PFAS.  We highlight emerging hybrid treatments to remove PFAS from water.

     

Polychlorinated Biphenyls (Pcbs) Pollution in Sea of Japan

Abstract

Deep waters of the Sea of Japan and surface waters of the Pacific Coast of Honshu and the northeast Sea of Japan were analysed for polychlorinated biphenyls (PCBs) pollution. the ΣPCB concentrations in solution in the Sea of Japan (50–3000 m) were between 140 and 1230 fg dm_?3. the space-integrated surface water concentration near the Pacific coast of northern Honshu was 140 fg dm_?3and for the surface water of the Sea of Japan was 230 fg dm_?3. Based on these analyses four water masses were deduced in the Sea of Japan during the summer months. It is shown for the first time in the Sea of Japan that polychlorinated biphenyls are excellent chemical indicators of not only the anthropogenic pollution, but also water masses.     

Biopolymer-supported TiO2 as a sustainable photocatalyst for wastewater treatment: a review

The rising water pollution by pesticides, pharmaceuticals and dyes is a major health issue calling for advanced remediation methods such as photocatalysis with titanium dioxide (TiO₂), yet the use of TiO₂ displays issues of aggregation, mass loss, recovery, and reusability. These issues have been recently solved by synthesizing biopolymer-supported photocatalysts using cheap, biodegradable and safe biopolymers such as chitosan, alginate, cellulose, cyclodextrin, guar gum and starch. Here we review biopolymer-supported TiO₂ photocatalysts for the removal of organic compounds, with focus on preparation methods, photo and chemical stability, reusability, and adsorptive capacity. We discuss applications of immobilized photocatalysts at the industrial scale.

     

Regression models for octanol‐water partition coefficients,and for bioconcentration in fish

Octanol‐water partition coefficients (P) of a number of organochlorine insecticides (OCs) are presented. The merits of log‐log regressions between experimental ? values and calculated estimates of P, solute activity coefficients in water, solute molecular surface area data, and reversed‐phase liquid‐chromatographic net retention data, are critically evaluated for several classes of pollutants: polycyclic aromatic hydrocarbons (PAHs), chlorinated benzenes, chlorinated biphenyls and OCs. Special attention is paid to the predictive accuracy of such semi‐empirical regressions in connection with possible effects of solute molecular shape and polarity.

Finally, bioconcentration and ‐accumulation of hydrophobic pollutants in fish are briefly discussed.     

Inductively coupled plasma‐atomic emission spectroscopy in air and water pollution analysis†

The inductively coupled plasma (ICP), when employed as an excitation source in optical atomic emission spec.troscopy (AES), is finding widespread utilization for single and multielement inorganic trace analysis of pollutants. The recent availability of commercial ICP‐AES instrument systems has stimulated applications for the determination of metals and metalloids in diverse materials ranging from air particulates and fly ash to industrial effluents, sewage, and hard, soft, and saline waters.

The capabilities and limitations of ICP‐AES for applications in air and water pollution analysis are reviewed, and a number of recent examples presented.     

Biofuel production,hydrogen production and water remediation by photocatalysis,biocatalysis and electrocatalysis

The energy crisis and environmental pollution have recently fostered research on efficient methods such as environmental catalysis to produce biofuel and to clean water. Environmental catalysis refers to green catalysts used to breakdown pollutants or produce chemicals without generating undesirable by-products. For example, catalysts derived from waste or inexpensive materials are promising for the circular economy. Here we review environmental photocatalysis, biocatalysis, and electrocatalysis, with focus on catalyst synthesis, structure, and applications. Common catalysts include biomass-derived materials, metal–organic frameworks, non-noble metals nanoparticles, nanocomposites and enzymes. Structure characterization is done by Brunauer–Emmett–Teller isotherm, thermogravimetry, X-ray diffraction and photoelectron spectroscopy. We found that water pollutants can be degraded with an efficiency ranging from 71.7 to 100%, notably by heterogeneous Fenton catalysis. Photocatalysis produced dihydrogen (H₂) with generation rate higher than 100 μmol h⁻¹. Dihydrogen yields ranged from 27 to 88% by methane cracking. Biodiesel production reached 48.6 to 99%.

     

Dispersive solid phase extraction of chlorophenols using carbon-coated magnetic nanoparticles

Abstract

Carbon-coated magnetic nanoparticles were modified with cationic surfactant and used for the dispersive solid phase extraction of chlorophenols from aqueous samples. Surfactant adsorbed on the surface of the nanoparticles resulted in mixed hemimicelles for high extraction efficiency of chlorophenols. Under optimized conditions, calibration curves were linear from 0.5–20?mg L^?1 for analytes with limit of detection between 0.2 and 0.4?mg L^?1. The method was applied to extraction of chlorophenols from tap water, well water and industrial effluent. Recoveries were in the range of 94.0–99.4%, suggesting that sample matrix had little effect on the yields of extraction.     

Runoff water management technologies for dryland agriculture on the Loess

SUMMARY

Arid and semi-arid environments undergo periodic seasonal agricultural droughts of varying extents and duration, erratic and ineffective rainfall of high intensity and short duration, with high surface runoff. High efficiency water-harvesting agriculture has been routinely used in the Loess Plateau agricultural production of China over the past 10 years. Localized habitat effect and regional water resource enrichment are the theoretical basis of high efficient water-harvesting agriculture. Features of this agricultural system are described, including: water harvesting of surface runoff from roads and collection in concrete yards on plastic sheets; water storage cellar tanks for harvesting runoff to provide life-saving/critical irrigation, with devices for water lifting and conveying such as hand pumps and pipelines; feasible methods of water use for limited supplies such as drip, hole, subsoil, and super-sheet irrigation; agronomic measures of high water use efficiency; and field micro-catchment for water harvesting and conservation to increase fallow efficiency in rainy seasons. Using the stored runoff water to irrigate the mulched winter wheat and spring corn, as well as vegetables and fruit trees, significant yield increasing and water use efficiency improvements have been achieved. Plastic mulching for increasing fallow efficiency in rainy seasons and improving yield of the next winter wheat crop have been developed and demonstrated. These techniques have provided obvious benefits in terms of soil and water conservation on slope farmland in the hill regions and remarkable effects of storing water and reducing drought in the dryland farming regions have been obtained.     

The impact of artisanal gold mining,ore processing and mineralization on water quality in Marmato,Colombia

Marmato, Colombia, has been an important centre of gold mining since before the first Spanish colonizers arrived in 1536. The Marmato deposit is hosted in a dacite and andesite porphyry stock as sheeted sulphide-rich veinlet systems. The district is currently experiencing a surge in both major mining projects and artisanal mining, driven by sustained high gold prices. Ore from small-scale and artisanal gold mining is processed in numerous small mills (entables) around Marmato, which impact surface water quality through the discharge of milled waste rock slurry, highly alkaline cyanide-treated effluent, and high dissolved metal loads. To investigate the impact of artisanal mining and ore processing, water samples were collected in January 2012 from streams around Marmato. The average dissolved metal concentrations in impacted streams were Zn, 78 mg L^?1; Pb, 0.43 mg L^?1; Cu, 403 µg L^?1 Cd, 255 µg L^?1; As, 235 µg L^?1; Ni, 67 µg L^?1; Co, 55 µg L^?1; Sb, 7 µg L^?1; and Hg, 42 ng L^?1, exceeding World Health Organization drinking water guidelines. In addition, arsenic speciation was conducted in-situ and indicated that 91–95% of inorganic arsenic species is in the form of As(V). Spatial analysis of the data suggests that entables processing ore for artisanal miners are the main contributor to water pollution, with high sediment loads, alkalinity and elevated concentrations of dissolved arsenic, cadmium, mercury and lead, caused by the processing of gold-bearing sulphides in the entables. Geochemical data from surface water were compared to a comprehensive data set of whole rock analyses from drill core and channel samples from the deposit, indicating that the deposit is significantly enriched in gold, silver, lead, zinc, arsenic, antimony, and cadmium compared to crustal averages, which is reflected in the surface water geochemistry. However, elevated mercury levels in surface water cannot be explained by enrichment of mercury in the deposit and strongly suggest that mercury is being added to concentrates during ore processing to amalgamate fine gold.

     

Reassessment of the Ocean-To-Atmosphere Flux of Carbon Monoxide

Abstract

Carbon monoxide (CO) in the surface sea waters is produced predominantly by photochemical processes, oxidized by micro-organisms and outgassed to the atmosphere. to assess carbon monoxide flux from the oceans to the atmosphere, the photochemical production and microbial oxidation of carbon monoxide in the oceanic mixed-layer was investigated during several oeanographic cruises and in the laboratory. the photoproduction rate of carbon monoxide was found to be well correlated to the concentration of dissolved organic carbon (DOC) in coastal and open ocean surface waters. Taking a global average carbon monoxide production rate of 10 ± 2 nmole litre^?1 (mg DOC hr)^?1 in the surface open ocean water, and 25 ± 7 nmole litre^?1 (mg DOC hr)^?1 in coastal sea water, at cloud-free summer solar noon, the photochemical production of carbon monoxide in the global oceans is estimated to be at a rate of 1200 ± 200 Tg CO y^?1. the microbial carbon monoxide turnover time in the mixed-layer was observed to range from hours in a coastal estuary to 16 days in the Pacific along 1057deg; W in dark incubations. Natural sunlight can largely inhibit the microbial consumption of carbon monoxide in surface water. On a global scale, microbial consumption is responsible for the loss of less than 10% of photochemical produced carbon monoxide in the surface ocean. Field measurements have shown that the net transport of carbon monoxide from the euphotic zone to the underlying deeper ocean water is limited and that the overall life time in surface sea waters is less than 3-4 hours. When combined, these field measurements with the photoproduction and microbial consumption rates obtained, we estimate the oceanic flux to the atmosphere is about 1000 ± 200 Tg CO y^?1, which represents the largest single source of atmospheric carbon monoxide.     

Zur funktion des afterschornsteinschleuderns bei diademseeigeln

In some diadematid sea urchins, the anus opens at the top of the anal cone, i.e., a chimney-like elevation of the periproctal membrane. With this anal cone, Diadema setosum can perform a rotatory movement which often lasts more than 1 h. During rotation, the anal cone inclines towards the rotation axis which yields a device similar in function to a centrifugal pump that can throw water out of the rectum. The calculation of the hydrodynamic mechanism pertinent to the parameters given for D. setosum shows that anal-cone rotation is sufficiently effective to empty the rectum and a great part of the hind gut within a short time. This allows a more rapid water change in the second intestinal circuit, which could provide several advantages: (1) increased rinsing results in better evacuation of soluble metabolic end products which, in turn, promotes their excretion by the hind gut; (2) provision of oxygen-rich water to the intestine improves the oxygen supply to the perivisceral cavity in cases of increased oxygen demand; (3) faecal pellets are expelled into the free water and do not sink to the aboral body surface, where they would be difficult to remove because of the lack of tridentate pedicellaria. The rotating anal cone — in D. setosum encireled by an orange iris-like ring — probably resembles a rolling eye, which may deter predators.

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Mit Unterstützung der Gesellschaft der Freunde der Zoologischen Staatssammlung München e. V.     

Sulfonated graphene nanomaterials for membrane antifouling,pollutant removal,and production of chemicals from biomass: a review

Water pollution and the unsustainable use of fossil fuel derivatives require advanced catalytic methods to clean waters and to produce fine chemicals from modern biomass. Classical homogeneous catalysts such as sulfuric, phosphoric, and hydrochloric acid are highly corrosive and non-recyclable, whereas heterogeneous catalysts appear promising for lignocellulosic waste depolymerization, pollutant degradation, and membrane antifouling. Here, we review the use of sulfonated graphene and sulfonated graphene oxide nanomaterials for improving membranes, pollutant adsorption and degradation, depolymerization of lignocellulosic waste, liquefaction of biomass, and production of fine chemicals. We also discuss the economy of oil production from biomass. Sulfonated graphene and sulfonated graphene oxide display an unusual large theoretical specific surface area of 2630 m²/g, allowing the reactants to easily enter the internal surface of graphene nanosheets and to reach active acid sites. Sulfonated graphene oxide is hydrophobic and has hydrophilic groups, such as hydroxyl, carboxyl, and epoxy, thus creating cavities on the graphene nanosheet’s surface. The adsorption capacity approached 2.3–2.4 mmol per gram for naphthalene and 1-naphthol. Concerning membranes, we observe an improvement of hydrophilicity, salt rejection, water flux, antifouling properties, and pollutant removal. The nanomaterials can be reused several times without losing catalytic activity due to the high stability originating from the stable carbon–sulfur bond between graphene and the sulfonic group.

     

Environmental risk induced by TiO2 dispersions in waters and sediments: a case study

A southern Italian area that is characterized by large outcrops of rocks that are rich in titanium oxide (TiO₂) phases were investigated to determine the mineralogical risk induced by the natural dispersion of TiO₂ minerals. Rock, sediment and surface water samples were collected to determine the physicochemical and mineralogical factors (i.e., size distribution, morphology and alteration) indicative of potential TiO₂ toxicity. X-ray diffraction data suggested that titanium oxides were present as rutile and anatase. Scanning electron microscopy images showed elongated TiO₂ morphologies; fibres were found as either isolated or embedded/enclosed in flake-like phyllosilicates. The concentration of fibres in stream water ranged from 1.7 to 4.6 million fibres per litre. The highest fibre amounts in the sediments were in the <8-µm fraction, while single fibres were primarily concentrated in the <2-µm fraction. The results indicate that titanium oxide minerals represent a natural source of environmental risk and that the geomineralogical characterization of rich TiO₂ areas is indispensable for understanding their geoavailability, dispersion and distribution.

     

Toxiwasp∗

TOXIWASP combines most of the kinetic structure of EXAMS 2 with the transport capabilities of WASP (Water Analysis Simulation Program). TOXIWASP uses variable chemical degradation rates from chemical properties and the environmental conditions of the aquatic ecosystem. These rates are reduced from pseudo first‐order rates to first‐order rates including the processes hydrolysis, biotransfor‐mation, phototransformation, oxidation, and volatilisation. Assuming ultimate local equilibrium, and using a chemical dependent partition coefficient as well as spatially varying environmental carbon fractions, sorption onto sediments and biomass is calculated. Environmental alternations could be specified in any time scale by providing monitoring data.

TOXIWASP generates total sediment and chemical concentrations every time step in every segment, including surface water, subsurface water, surface bed and subsurface bed. Advection, dispersion, mass loading, sedimentation, and scour affect sediment concentration in the water column and in the bed sediment concentrations depend on burial and erosion. In addition chemical concentrations are influenced by degradation, sediment‐water dispersion, and percolation. Lateral transport of chemical within the bed is neglected and transport data are not calculated in the program. TOXIWASP is developed to model stratified lakes, reservoirs, large rivers, estuaries, and coastal waters. As for EXAMS 2 (Burns et al.²) the TOXIWASP user has to accept the model's inability to connect the water body to a chemically contaminated atmosphere.     

On the Pollution Caused by Organic Materials in Chinhae Bay,Korea

In August 1989, oxygen deficient conditions of bottom waters occurred in the Chinhae Bay together with a steep pycnocline. Dissolved oxygen contents were lower than 1 ml/l from 3 m depth in the inner Masan Bay and from 10 m depth in the outer Masan Bay. in Kohyonsong Bay, surface salinity was about 29%_° and an oxygen deficient condition occurred in the bottom waters. Near Somodo Island, surface waters containing more than 30 μ/l of chlorophyll α and over 50 μmol/l of nitrate could be distinguished. in Masan Bay ammonia and phosphate concentrations increased with increasing depth suggesting the active degradation of organic materials in the bottom waters and leaching from sediments.

In Kohyonsong Bay, nitrate contents ranged from 1.9 to 5.4 μmol/l in the surface waters and subsurface maximum of chlorophyll α could be observed. ETS activity was 286.1 μl O₂/l-h in the surface waters of Masan Bay and respiratory oxygen consumption is likely to proceed at a rate of 1320 ml O₂/m²-d in the bottom waters of this bay. Primary productivity was 15.60 gC/m²-d in the inner Masan Bay and 0.75 gC/m²-d in Kohyonsong Bay.

In Masan Bay, amino acids content in the sinking materials collected by the sediment trap deployed at the bottom layer was 264 mgC/m²-d. This amount is equivalent to 6.8% of the amino acids produced in the water column by primary production. in Kohyonsong Bay 95 mg/Cm²-d of amino acids was collected corresponding to 50.8% of amino acids produced in the water column. in Kohyonsong Bay large faecal pellets produced in shellfish farms were easily settled in the sediment because of the weak current regime.     

Assessment of Young Dong tributary and Imgok Creek impacted by Young Dong coal mine,South Korea

An initial reclamation of the Young Dong coal mine site, located in northeastern South Korea, was completed in 1995. Despite the filling of the adit with limestone, acid rock drainage (ARD) enters Young Dong tributary and is then discharged to Imgok Creek. This ARD carries an average of 500 mg CaCO₃/l of mineral acidity, primarily as Fe(II) and Al. Before spring runoff, the flow of Imgok Creek is 3.3–4 times greater than that of the tributary and has an alkalinity of 100 mg CaCO₃/l, which is sufficient to eliminate the mineral acidity and raise the pH to about 6.5. From April through September 2008, there were at least two periods of high surface flow that affects the flow of ARD from the adit. Flow of ARD reaches 2.8 m³/min during spring runoff. This raised the concentrations of Fe and Al in the confluence with Imgok Creek. However, by 2 km downstream the pH of the Imgok Creek is 6.5 and only dissolved Fe is above the Korean drinking water criteria (0.30 mg/l). This suggests only a minor impact of Young Dong Creek water on Imgok Creek. Acid digestion of the sediments in Imgok Creek and Young Dong Tributary reveals considerable abundances of heavy metals, which could have a long-term impact on water quality. However, several water-based leaching tests, which better simulate the bioavailable metals pool, released only Al, Fe, Mn, and Zn at concentrations exceeding the criteria for drinking water or aquatic life.

     

Application of High-Volume Fly Ash Concrete to Marine Structures

A new material with high content of fly ash named ‘Ashcrete’ has been developed. to examine the applicability of Ashcrete to marine structures, strength characteristics, resistance to sea water attack, and safety in the marine environment have been studied. the following results have been obtained:

1) the strength characteristics of high-volume fly ash concrete depend upon the type and proportions of chemical activators as well as curing conditions.

2) Ashcrete using sodium chloride (NaCI) as a chemical activator shows high initial strength and good strength development with age.

3) Ashcrete containing NaCI activator shows good resistance to sea water from the viewpoint of its strength characteristics, volume changes and microstructurcs.

4) Since 1980 many types of large-scale artificial reefs made of Ashcrete have been installed in the sea. As a result of long-term studies and underwater observations, the Japanese Government has demonstrated the durability of the material, safety in the marine environment and attractiveness to fish.

5) It is therefore proposed that Ashcrete might be used in constructing large-scale sea mounts in deep water for the purpose of generating upwelling.