Synthesis and utilization of a mesoporous nickel oxide as a novel catalyst for degradation of phenol

Mesoporous nickel oxide (MNO) was synthesized by sol–gel method with saponificated chlorophyll-a (Chl-a) as template and Ni (II) acetate as starting material. XRD, surface area, pore volume, pore diameter and pore size distribution of MNO were determined. It exhibited high surface area and uniform pores with very sharp pore size distribution centered at 3.6 nm. High resolution transmission electron microscope images confirmed the results. MNO showed a high activity toward degradation of phenol at low temperature under atmospheric pressure of oxygen.     

Accumulation of iron and arsenic in the Chandina alluvium of the lower delta plain, Southeastern Bangladesh

Accumulations of iron, manganese, and arsenic occur in the Chandina alluvium of southeastern Bangladesh within 2.5 m of the ground surface. These distinctive orange-brown horizons are subhorizontal and consistently occur within 1 m of the contact of the aerated (yellow-brown) and water-saturated (gray) sediment. Ferric oxyhydroxide precipitates that define the horizons form by oxidation of reduced iron in pore waters near the top of the saturated zone when exposed to air in the unsaturated sediment. Hydrous Fe-oxide has a high specific surface area and thus a high adsorption capacity that absorbs the bulk of arsenic also present in the reduced pore water, resulting in accumulations containing as much as 280 ppm arsenic. The steep redox gradient that characterizes the transition of saturated and unsaturated sediment also favors accumulation of manganese oxides in the oxidized sediment. Anomalous concentrations of phosphate and molybdenum also detected in the ferric oxyhydroxide-enriched sediment are attributed to sorption processes.     

Review on research and application of mesoporous transitional metal oxides in water treatment

This paper reviews the application of meso- porous transitional metal oxides in water treatment on basis of the catalysis and adsorption. Mesoporous transitional metal oxides are characterized by their intrinsic features, such as a high surface area, a highly ordered array of unidimensional pores with a very narrow pore size distribution, and highly dispersed active sites. Finally, the suggestions of further study on application are proposed.     

底泥中重金属毒性的室内孔隙水分析技术

根据孔隙水中重金属的浓度可以判定底泥中重金属的毒性但获得真正的底泥孔隙水十分困难。本文提供了一套简便易行的室内原状孔隙水取样技术，将碳化硅砂芯埋入底泥，添加表层水并静置９０ｄ，通过渗滤获得孔隙水，测定孔隙水中重的浓度，所得结果与微生态系统暴露试验中生物指示的重金属的毒性大小相吻合，与生物积累重金属的浓度显著正相关。     

PVDF ultrafiltration membranes of controlled performance via blending PVDF-g-PEGMA copolymer synthesized under different reaction times

PVDF blended different graft ratio of PVDF-g-PEGMA were systematically studied. Tuning the amphiphilic copolymer synthesis time to control membrane performance. The PVDF membrane with PVDF-g-PEGMA at 19 h possesses most surface oxygen content. The synthesis time of PVDF-g-PEGMA at 9 h is good for high flux UF membrane. Polyvinylidene fluoride grafted with poly(ethylene glycol) methyl ether methacrylate (PVDF-g-PEGMA) was synthesized using atomic transfer radical polymerization (ATRP) at different reaction times (9 h, 19 h, and 29 h). The corresponding conversion rates were 10%, 20% and 30%, respectively. PVDF was blended with the copolymer mixture containing PVDF-g-PEGMA, solvent and residual PEGMA under different reaction times. In this study, we explored the effect of the copolymer mixture additives with different synthesis times on cast membrane performance. Increasing the reaction time of PVDF-g-PEGMA causes more PVDF-g-PEGMA and less residual PEGMA to be found in the casting solution. Incremental PVDF-g-PEGMA can dramatically increase the viscosity of the casting solution. An overly high viscosity led to a delayed phase inversion, thus hindering PEGMA segments in PVDF-g-PEGMA from migrating to the membrane surface. However, more residual PEGMA contributed to helping more PEGMA segments migrate to the membrane surface. The pure water fluxes of the blended membrane with reaction times of 9 h, 19 h, and 29 h are 5445 L·m⁻²·h⁻¹, 1068 L·m⁻²·h⁻¹and 1179 L·m⁻²·h⁻¹, respectively, at 0.07 MPa. Delayed phase inversion can form smaller surface pore size distributions, thus decreasing the water flux for the membranes with PVDF-g-PEGMA at 19 h and 29 h. Therefore, we can control the membrane pore size distribution by decreasing the reaction time of PVDF-g-PEGMA to obtain a better flux performance. The membrane with PVDF-g-PEGMA at 19 h exhibits the best foulant rejection and cleaning recovery due to its narrow pore size distribution and high surface oxygen content.     

淀山湖上覆水与沉积物孔隙水中重金属的分布特征

研究了淀山湖上覆水和沉积物孔隙水中Pb ,Cd,Cr,Cu ,Fe和Mn的浓度及Eh 分布 ,分析了孔隙水中重金属的扩散通量 .结果表明 ,淀山湖中重金属的浓度由高到低依次为 :Mn >Fe >Cr,Cu ,Pb >Cd ;Fe和Mn在孔隙水中的浓度远远大于它们在上覆水中的浓度 ,表层沉积物孔隙水中Pb ,Cd ,Cr,Cu的浓度稍大于它们在上覆水中的浓度 ;沉积物中的重金属可能按照浓度梯度经孔隙水从沉积物向上覆水中扩散而最终影响上覆水的水质     

载铜活性炭纤维Cu-ACF的微观结构与表面形态

本文讨论了载铜活性炭纤维的制备过程与微观结构，表面形态的关系。     

Colloid-enhanced ultrafiltration in removal of traces amounts of borates from water

The use of colloid-enhanced ultrafiltration for boron removal from water is investigated. Biodegradable surfactant, 1,4-sorbitol oleate, was applied to obtain micelles and high molecular weight chitosan to reinforce their stability. Two kind of membranes were compared: neat porous polysulfone membrane and charged porous sulfonated polysylfone membrane; both with similar average pore diameter of 5 nm. The studies revealed that two key factors affect the boron rejection: presence of surfactant in the colloidal mixture and a repulsion effect of sulfone groups on the membrane surface. Both have a positive effect on boron removal.     

Influence of pore size and membrane surface properties on arsenic removal by nanofiltration membranes

Four NF membranes were compared regarding arsenate rejection and their properties. Rejection of arsenate had no relationship with membrane pore size. A more negative surface charge was favorable for arsenate rejection at neutral pH. A severe membrane fouling could lead to a great reduction of arsenic rejection. Nanofiltration (NF) has a great potential in removing arsenate from contaminated water. The performance including arsenate rejection, water permeability and resistance to fouling could however differ substantially among NF membranes. This study was conducted to investigate the influence of membrane pore size and surface properties on these aspects of membrane performance. Four fully-aromatic NF membranes with different physicochemical properties were adopted for this study. The results showed that surface charge, hydrophobicity, roughness and pore size could affect water permeability and/or arsenate rejection considerably. A more negative surface charge was desirable to enhance arsenate rejection rates. NF90 and a non-commercialized membrane (M#1) demonstrated the best performance in terms of arsenate rejection and water permeability. The M#1 membrane showed less membrane fouling than NF90 when used for filtration of real arsenic-containing groundwater. This was mainly due to its distinct chemical composition and surface properties. A severe membrane fouling could lead to a substantial reduction of arsenic rejection. The M#1 membrane showed the best performance, which indicated that membrane modification could indeed enhance the overall membrane performance for water treatment.     

Recovery and reuse of floc sludge for high-performance capacitors

• The feasibility of facile fabrication of capacitor from floc sludge is discussed. • The porous carbon composites are obtained by acidification and KOH activation. • The as-prepared 3D structure has large surface area and optimal pore size. • Admirable specific capacitance and outstanding cycling stability are obtained. In this paper, floc sludge was transformed into porous carbon matrix composites by acidification and KOH activation at high temperature and used as an electrode material for application in capacitors. The effects of different treatment processes on the electrochemical properties of sludge materials were compared. The results of electrochemical tests showed that the sludge electrode exhibited excellent energy storage performance after HNO₃ acidification and KOH activation with a mass ratio of 3:1 (KOH/C). The specific capacitance of the sludge electrode reached 287 F/g at a current density of 1 A/g. In addition, the sludge electrode material showed excellent cycle stability (specific capacity retained at 93.4% after 5000 cycles at 5 A/g). Based on XRD, FTIR, SEM, TEM, and BET surface analysis, the morphology of sludge electrode materials can be effectively regulated by chemical pretreatment. The best-performing material showed a 3D porous morphology with a large specific surface area (2588 m²/g) and optimal pore size distribution, improving ion channels and charge conductivity. According to the life cycle assessment of floc sludge utilization, it reduced the resource consumption and toxicity risk by more than 90% compared with ordinary sludge disposal processes. This work provided a cost-effective and eco-friendly sludge reuse method and demonstrated the application potential of sludge-based materials in high-performance supercapacitors.     

Recovery efficiency of the hydrofluorocarbon (HFC‐134a) by activated carbons of different physicochemical properties

The adsorption characteristics of 1,1,1,2‐tetrafluoroethane (HFC‐134a) on activated carbon were investigated to evaluate the recovery efficiency of HFC‐134a by six activated carbons (two granular activated carbons (GAC1 and GAC2), one high‐surface area activated carbon (HAC), and three activated carbon fibers (ACF10, ACF15, and ACF20)). HFC‐134a adsorption on the activated carbons increased with increase in the specific surface area and pore volume of the activated carbon. The differential heat of the HFC‐134a adsorption decreased with increase in the percentage of the micropore volume to the total pore volume. The adsorption model of HFC‐134a on the activated carbon could be based on the Langmuir model. The constant a of the Langmuir plot of HAC and ACF20 is smaller than GAC1 or GAC2 and ACF10 or ACF15, respectively. The constant W_s of HAC has the largest value. The constant a was correlated to the heat of adsorption. It is concluded that the largest amount of HFC‐134a was adsorbed on HAC, and the least amount of interaction occurred between HFC‐134a and the HAC. The amount of HFC‐134a adsorbed on the activated carbons over time was applied to the Sameshima equation. The adsorption rate constant of HFC‐134a on HAC was the largest. The HAC could be suitable for the recovery of HFC‐134a.     

Fabrication,characterization and evaluation of mesoporous activated carbons from agricultural waste: Jerusalem artichoke stalk as an example

This work explores the feasibility of Jerusalem artichoke stem (JAS), an agricultural waste, as an alternative precursor for fabrication of mesoporous activated carbon (MAC) via conventional ZnCl₂ activation. The as-prepared JAS-MACs were characterized by thermogravimetric, nitrogen gas adsorption isotherm and high resolution scanning electron microscopy analysis. The interacting effects of chemical dosage, activation temperature and time on the mesoporosity, mesopore volume and carbon yield were investigated, and further optimized by response surface methodology (RSM). The Brunauer-Emmett-Teller surface area, mesoporosity and mesopore volume of the JAS-MAC prepared under optimum condition were identified to be 1631 m²·g^-1, 90.16% and 1.11 cm³·g^-1, respectively. Compared with commercial activated carbons, this carbon exhibited a comparable monolayer adsorption capacity of 374.5 mg·g^-1 for Methylene Blue dye. The findings suggest that RSM could be an effective approach for optimizing the pore structure of fabricated activated carbons.     

Decolouring mechanism of Zhejiang diatomite. Application to printing and dyeing wastewater

We report the adsorption isotherm of methylene blue on the surface of Zhejiang and Jilin diatomite. The relationship between the adsorption isotherm and diatomite pore structure is discussed. The degree of decolouring was found to be strongly related to pH and isoelectrical value. Furnace ash residue and diatomite were found to be very effectively treating printing and dyeing wastewater.     

Hydrogen sulfide removal by iron containing activated carbon

Activated carbon modified by impregnation with iron (III) chloride solution (Fe‐ACs) were studied to try to raise their adsorption capacity for hydrogen sulfide, a malodorous substance.

The surface area and pore volume of activated carbon were decreased by impregnation, but the amount of hydrogen sulfide adsorbed onto Fe‐AC was larger than that onto raw activated carbon (R‐AC). In particular, a large increase of the amount adsorbed onto Fe‐AC was noted at low equilibrium pressure. It was assumed that the increase of amount of hydrogen sulfide adsorbed onto Fe‐AC was due to the chemical interaction between iron (III) chloride on the pores in addition to the physical adsorption onto pores of activated carbon. Fe‐AC shows a high selectivity for hydrogen sulfide.     

Insight into the promotion mechanism of activated carbon on the monolithic honeycomb red mud catalyst for selective catalytic reduction of NOx

• Activated carbon was proposed to be an efficient accelerant for molded red mud catalyst. • The surface acidity and reducibility were highly improved, as well as the pore structure. • The enrichment of the surface Fe²⁺ and the adsorbed oxygen account for the improvement. Our previous study proved that the acid-pretreatment process could efficiently activate red mud (RM) for the selective catalytic reduction (SCR) of NO_x. However, in terms of the molding process, which is the key step determining whether it can be applied in large-scale industrial, the surface acidity and reducibility of catalyst always decreased dramatically, and part of surface area and pore structure were lost. In this study, we prepared monolithic honeycomb red mud (MHRM) catalysts with activated carbon (AC) as an accelerant and investigated the effect of AC on the MHRM. The results showed that the MHRM with 3 wt.% of AC (MHRM-AC3) exhibited the best SCR performance, and kept more than 80% NO_x conversion in the range of 325°C–400°C. Compared with the MHRM, MHRM-AC1, and HMRM-AC5, the MHRM-AC3 has more mesoporous and macroporous structures, which can provide more adsorption active sites. The AC significantly improved NH₃ adsorption and surface reducibility, which was mainly due to the increase of the surface acid sites (especially the Brönsted acid sites), the concentration of Fe(II), and the surface adsorbed oxygen. The presence of more Fe(II) enriched the surface oxygen vacancies, as well as the surface adsorbed oxygen, due to the charge imbalance and unsaturated chemical bond. And surface adsorbed oxygen exhibited more active than lattice oxygen owing to its higher mobility, which was conducive to NO_x reduction in the SCR reaction.     

Geophysical investigations for evaluation of environmental pollution in a mine tailings area

Sulfide-containing mill wastes of the Komsomolsk ore processing plant situated in the Kemerovo region (Russia) were examined in 2013–2015. Multipurpose studies of the mine tailings determined the composition of waste, pore water, mine drainages, and affected groundwater. Electrical resistivity tomography was used to trace the geoelectric zoning of the waste samples. Layers with low resistivity indicated areas with pore spaces filled with highly mineralized solutions with Fe, Cu, Zn, Cd, As, and Sb at total concentrations of up to 50 g/L. Anomalous zones can be specified as ‘geochemical barriers’ – specific layers where the mobility of the elements is reduced due to pH conditions, redox potential, and Fe(III) hydroxide precipitation. The zones of increased conductivity in oxidized mine tailings indicated local areas with high acid production potential and coexisting acidic pore solution. In non-oxidized tailings, high conductivity of the mineral skeleton was observed. There was a migration of drainage outside the tailings, its direction monitored by geophysical data. Chemical analysis confirmed that the concentrations of As in groundwater samples were higher than the maximum permissible concentration.     

Metal partitioning in sediment pore water from the Ondo coastal region,Nigeria

Distribution and equilibrium partitioning of metals (Cd, Cu, Cr, Fe, Ni, Pb, Mn, and Zn) between pore water and surface sediments at the Ilaje coast of Ondo State, Nigeria, were studied. The Ilaje River can be one of the interesting research locations because of its economic nature and history of oil pollution. Seasonal variations were observed to investigate possible variations in the availability of metals for organisms throughout the year. The concentrations in both sediments and pore water during the dry and wet seasons were as follows: Cu?>?Fe???Mn?>?Pb?>?Ni?>?Cr?>?Cd?>?Zn. The pore water–sediment partition coefficient (K _p) showed that Zn and Cd were highly mobile while Fe and Cu have restricted mobility. Dissolved organic carbon (DOC) in pore water had a strong influence on mobility and bioavailability of all the metals (p?K _oc), increased levels of Fe and Cu were linked to lithological origin. Concentrations of Pb and Ni were associated with petroleum-related sources. The significance of the field-based techniques for ecotoxicological purposes is discussed.     

Specialized feeding mechanism in the pelagic copepod genus Heterorhabdus (Calanoida: Heterorhabdidae), with special reference to the mandibular tooth and labral glands

Scanning and transmission electron microscopy and gut-content analysis revealed the fine structure of the mandibular ventralmost tooth and labral glands of the carnivorous copepods Heterorhabdus spp. on the basis of the specimens collected in the waters near Nansei Islands, Southwestern Japan, in November 1993. The ventralmost tooth is hollow with a subterminal pore and a basal opening. The distal region of the tooth is like a hypodermic needle and is strengthened by opal layers. The tip of the tooth including the subterminal pore usually protrudes from between the labrum and the paragnath, while the basal region of the ventralmost tooth and the whole parts of the other teeth are semi-enclosed in the preoral food chamber formed by the labrum and the paragnath. There is a large glandular cell in the basal region of the mandibular gnathobase, but no direct connection exists between the gnathobasal cells and the tubular lumen of the ventralmost tooth. The posterior surface of the labrum carries a lateral pair of large glandular pores, which are located close to, and appear to fit exactly the basal openings of the ventralmost teeth. Each of these glands has two massive secretory cells, and the secretory materials from these cells appear to be mixed before discharge from the pore. A specialized feeding mechanism is proposed, wherein venom or anaesthetic is injected from the labral-gland pores into the tubular lumen of the mandibular ventralmost tooth, and then relcased into the prey from its subterminal pore immediately after capture using the stout maxillae of prey macrozooplankters such as copepodids and polychaetes.     

Preparation of a permanent magnetic hypercrosslinked resin and assessment of its ability to remove organic micropollutants from drinking water

A rapid and effective method based on a novel permanent magnetic hypercrosslinked resin W150 was proposed for the removal of organic micropollutants in drinking water. W150 was prepared by suspension and post-crosslinking reaction and found to possess a high specific surface area of 1149.7 m²·g^-1, a small particle size of 50 μm to 100 μm, and a saturation magnetization as high as 8 emu·g^-1. W150 was used to eliminate nitrofurazone (NFZ) and oxytetracycline (OTC) from drinking water compared with commercial adsorbents XAD-4 and F400D. The adsorption kinetics of NFZ and OTC onto the three adsorbents well fitted the pseudo-second-order equation (r>0.972), and the adsorption isotherms were all well described by the Freundlich equation (r>0.851). Results showed that the reduction in adsorbent size and the enlargement in sorbent pores both accelerated adsorption. Moreover, the effect of particle size on adsorption was more significant than that of pore width. Given that the smallest particle size and the highest specific surface area were possessed by W150, it had the fastest adsorption kinetics and largest adsorption capacity for NFZ (180 mg·g^-1) and OTC (200 mg·g^-1). For the adsorbents with dominant micropores, the sorption of large-sized adsorbates decreased because of the inaccessible micropores. The solution pH and ionic strength also influenced adsorption.     

改性活性氧化铝除磷性能的试验

为提高活性氧化铝对废水中磷的去除效果,以硫酸铝为改性剂,采用浸渍法对其进行改性;测定了改性前后活性氧化铝的比表面积及孔容孔径;考察了吸附时间、pH、废水初始浓度、改性剂投加量等因素对去除废水中磷的影响;探讨了改性活性氧化铝对磷的吸附机理.结果表明,改性后活性氧化铝的比表面积为398.364 m2/g,提高了14.22%...