Ammonium Ion Adsorption and Settleability Improvement Achieved in a Synthetic Zeolite-Amended Activated Sludge

Municipal wastewater treatment plants typically exhibit two classic problems： high ammonium concen- tration in water after conventional biological treatment and, in some cases, poor activated sludge sediment ability. Potential solutions to these problems were investigated by adding a synthetic zeolite obtained from coal fly ash to different steps of activated sludge treatment. The experimental results for ammonium removal fit well with the theoretical adsorption isotherms of the Freundlich model with a maximum adsorption capacity of 13.72 mg.g-＇. Utiliza- tion of this kind of zeolite to improve activated sludge sediment ability is studied for the first time in this work. It is found that the addition of the zeolite （1 g. L-1） to an activated sludge with settling problems significantly enhances its sediment ability and comoact ability. This is confirmed by the sludge volume index （SVI）, which was reduced from 163 ml.g-1 to 70 ml.g-r, the V60 value, which was reduced from 894 ml.L-1 to 427 ml.L-1, and the zeta poten- tial （0, which was reduced from -19.81 mV to -14.29 mV. The results indicate that the addition of this synthetic zeolite to activated sludge, as an additional waste management practice, has a positive impact on both ammonium removal and sludge settleability.

Injectable bioactive polymethyl methacrylate-hydrogel hybrid bone cement loaded with BMP-2 to improve osteogenesis for percutaneous vertebroplasty and kyphoplasty

Poly methyl methacrylate(PMMA)bone cement is used in augmenting and stabilizing fractured vertebral bodies through percutaneous vertebroplasty(PVP)and percutaneous kyphoplasty(PKP).However,applications of PMMA bone cement are limited by the high elasticity modulus of PMMA,its low biodegradability,and its limited ability to regenerate bone.To improve PMMA bio activity and biodegradability and to modify its elasticity modulus,we mixed PMMA bone cement with oxidized hyaluronic acid and carboxymethyl chitosan in situ cross-linking hydrogel loaded with bone morphogenetic protein-2(BMP-2)to achieve novel hybrid cement.These fabric ated PMMA-hydrogel hybrid cements exhibited lower setting temperatures,a lower elasticity modulus,and better biodegradability and biocompatibility than that of pure PMMA cement,while retaining acceptable setting times,mechanical strength,and inj ectability.In addition,we detected release of BMP-2 from the PMMA-hydrogel hybrid cements,significantly enhancing in vitro osteogenesis of bone marrow mesenchymal stem cells by up-regulating the gene expression of Runx2,Coll,and OPN.Use of PMMA-hydrogel hybrid cements loaded with BMP-2 on rabbit femoral condyle bone-defect models revealed their biodegradability and enhanced bone formation.Our study demonstrated the favorable mechanical properties,biocompatibility,and biodegradability of fabricated PMMA-hydrogel hybrid cements loaded with BMP-2,as well as their ability to improve osteogenesis,making them a promising material for use in PKP and PVP.

Effect of Flooding Frequency and Nutrient Addition on Plant Growth and Total Petroleum Hydrocarbons Removal in Mangrove Microcosms

The addition of nutrients to accelerate biodegradation of oil is an adequate strategy to clean up polluted mangrove soils which pollutes mangrove soils. However, the hydrology of these ecosystems might interfere with such strategy. The effect of flooding frequency and nutrient addition on hydrocarbon removal in mangrove sediments was investigated in this study. Microcosms consisted of pots with 5 kg of fresh mangrove sediments and one seedling of Avicennia germinans. Treatments included: planted microcosms with fertilizer and crude oil (PNC), planted microcosms with oil (PC), non-planted microcosms with oil and fertilizer (NC), planted microcosms with fertilizer (PN) and planted microcosms without oil or fertilizer (P). Mexican Maya crude oil and inorganic nutrients were added in a single dose of approximately 5.0 g DW·kg-1, 0.33 g of N DW·kg-1 and 0.06 g P DW·kg-1. Microcosms were either permanently flooded (PF) or intermittently flooded (IF: 14 hours drained and 10 hours flooded), and kept in a glasshouse in Xalapa, Veracruz, Mexico. In both flooding conditions, oil decreased the relative growth rate of A. germinans by 56% in (PC) treatments and 40% in (PNC) treatments. Redox potential in the oiled treatments (-44.73 to +75.34 mV) was lower than non-oiled treatments (-1.31 to +163.43 mV). Total Petroleum Hydrocarbons (TPHs) removal in PC treatments was low in both permanent (2.99% ± 3.51%) and intermittently flooding conditions (11.75% ± 1.46%). The highest TPHs removal was observed in (PNC) and (NC) under IF conditions (47% ± 3.86% and 50.32% ± 7.15% after 4 months, respectively). It was concluded that nutrient addition increased TPHs removal but only under IF conditions and helped mangrove plants to deal with TPHs toxicity.

Syntheses and fluorescent properties of complexes of Eu(Ⅲ) with HTTA,TPPO and benzoic acid

A series of Eu（III） complexes of α-thenoyltrifluoroacetone（HTTA） with trioctylphosphine oxide（TPPO） and benzoic acid（BA） or its two derivatives, p-toluic acid（PTA） and p-methoxybenzoic acid（POA） were synthesized and were characterized with elemental analysis, IR spectroscopy, scanning electronic microscopy and fluorescent spectra. The complexes were revealed to be Eu（BA）（TTA）2TPPO2, Eu（PTA）（TTA）2TPPO2 and Eu（POA）（TTA）2TPPO2. The excitation and absorption spectra of the complex Eu（POA）（TTA）2TPPO2 in MeOH solution were investigated in detail. The experimental result showed that relatively cheap materials with sharp red luminescence could be prepared, when benzoic acid or its two derivatives were added in Eu（III） complexes of ct-thenoyltrifluoroacetone with trioctylphosphine oxide. The relative fluorescence intensity of the Eu（III） complexes decreased in the following order： Eu（POA）（TrA）2TPPO2〉 Eu（PTA）（TTA）ETPPO2〉Eu（BA） （TFA）2TPPO2.

Al_2O_3基Ni-Cu双金属催化剂上乙酰丙酸氢解(英)

Inexpensive γ-alumina-based nickel-copper bimetallic catalysts were studied for the hydrogenolysis of levulinic acid,a key platform molecule for biomass conversion to biofuels and other valued chemicals,into γ-valerolactone as a first step towards the production of 2-methyltetrahydrofurane.The activities of both monometallic and bimetallic catalysts were tested.Their textural and chemical characteristics were determined by nitrogen physisorption,elemental analysis,temperature-programmed ammonia desorption,and temperature-programmed reduction.The monometallic nickel catalyst showed high activity but the highest bγ-product production and significant amounts of carbon deposited on the catalyst surface.The copper monometallic catalyst showed the lowest activity but the lowest carbon deposition.The incorporation of the two metals generated a bimetallic catalyst that displayed a similar activity to that of the Ni monometallic catalyst and significantly low bγ-product and carbon contents,indicating the occurrence of important synergetic effects.The influence of the preparation method was also examined by studying impregnated- and sol-gel-derived bimetallic catalysts.A strong dependency on the preparation procedure and calcination temperature was observed.The highest activity per metal atom was achieved using the sol-gel-derived catalyst that was calcined at 450 ℃.High reaction rates were achieved;the total levulinic acid conversion was obtained in less than 2 h of reaction time,yielding up to 96%γ-valerolactone,at operating temperature and pressure of 250 ℃ and 6.5 MPa hydrogen,respectively.

电位质子滴定与NEXAFS和XPS表征功能化多壁碳纳米管比较(英文)

Since the discovery of carbon nanotubes (CNT), this material has been recognized as an attractive catalyst support. CNT must be functionalized before use as a catalyst support and typically this involves oxidation. However, the functional group distribution on the CNT is very complex mixture of groups and varies with oxidation agent used. Here a simple acid-base titration is introduced to characterize the oxygen functionalized CNT. By comparing characterization with near-edge X-ray absorption fine structure (NEXAFS) and X-ray photoelectron spectroscopy (XPS) for both at the C and O K-edges, it can be demonstrated that potentiometric proton titration can be a fast and quantitative analysis for Brnsted acid functional groups on CNT.

Influence of soil physicochemical properties,particle size fractions and mineralogy on the leaching potentials of arsenic and antimony in abandoned mine soils

At abandoned mine sites,arsenic(As)-and antimony(Sb)-enriched soils are often disposed of through onsite burial or capping.In highly weathered mine sites,the mobility of As and Sb is typically controlled by iron(Fe)(III)/Fe(II)phases;thus,the suitability of such disposal methods and appropriate testing techniques are questionable.In the present study,leaching potentials of As and Sb were examined using the toxicity characteristic leaching procedure(TCLP),waste extraction test(WET),and WET-extended procedure(WET-EXT)at three abandoned mine site soils in Australia.The leached concentration of As regularly exceeded USEPA criteria(5 mg L^(-1)).The highest leached concentrations of As and Sb were observed in the finest particle size fraction(<0.053 mm)by WET-EXT(1040 mg L^(-1)for As and 21.10 mg L^(-1)for Sb)followed by WET(800 mg L^(-1)for As and 20.90 mg L^(-1)for Sb).The TCLP method resulted in the lowest concentrations of leached As(0.0009 mg L^(-1))and Sb(0.0003 mg L^(-1)).Crystalline and amorphous As-bearing Fe oxides were the main phases in the soils studied.However,the best correlations of leached As determined by TCLP(0.832),WET(0.944),and WET-EXT(0.961)were found with the non-specifically sorbed(NS1)As fraction.The mineralogical and sequential extraction data clearly indicate the dominant role of Fe geochemistry in controlling leachability of As and Sb.The TCLP method was unlikely to be suitable for assessing leachability,as it exhibited no relationship with leachable Fe and substantially lower leached As and Sb than the other two methods.Given the high to extremely high leachable As and Sb concentrations,most of the soil samples would not be recommended for placement in capping works,old shafts,or reduction systems(e.g.,collection in drainage basins).

In flue nee of microwave drying and con venti onal drying methods on the mechanical properties of naproxen sodium drug tablets

Tablets are one of the most comm only used solid dosage forms taken by patients.The preparati on of high-quality tablets requires an understanding of the preparation process and elucidation of how the physical and mechanical properties change as a function of the preparation process.This work aims to investigate the impact of microwave irradiation drying and conventional drying methods(including freeze,convective and vacuum drying)on the hardness,tensile strength and friability of tablets made from a multi-component formulation containing naproxen sodium,microcrystalline cellulose,and polyvinylpyrrolidone.The results show that tablets subjected to microwave drying had the secondhighest tensile strength and hardness of 1.296 MPa and 67 N,respectively.The tablets subjected to vacuum drying had the lowest tensile strength and hardness of 1.21 MPa and 64 N,respectively.The friability index values for the tablets derived from the microwave and freeze-drying methods were<1%,while those for the tablets subjected to convective drying and vacuum drying methods were>l%.Microwave drying was observed to be an efficient method to produce naproxen sodium-containing tablets with satisfactory mechanical properties.These findings confirm that the drying method plays an essential role in the improvement or degradation of the mechanical properties of tablets.

Comparative analyses/evaluation of the textural properties of naproxen sodium tablets and powders prepared using microwave and other drying techniques

The properties of oral tablets are normally related to the properties of the powders they contain.Characterization of oral tablets is important for the development of tablets with rapid and safe release of the active ingredient.In this study,a new formulation of naproxen sodium was prepared and dried using microwave drying (MWD) and the following conventional drying techniques:freeze-drying (FD),vacuum drying (VD),and convective drying (CD).The reference drug powder (RDP) and dry granules MWG,CDG,VDG,and FDG,which were dried using MWD,CD,VD,and FD,respectively were compressed to form tablets labeled RF-TAB,MW-TAB,CD-TAB,VD-TAB,and FD-TAB,respectively.The dry granules and prepared tablets were characterized using Fourier transform infrared spectrometry,scanning electron microscopy,and X-ray diffraction.This study aimed to explore the correlation between the textural characteristics of the tablets and their respective powders for different drying methods.Although the morphologies of the dry particles were irregular,the prepared tablets were smooth and flat with few cracks.Drying increased the amorphous nature of the granules but decreased their crystallinity.The crystallinities of all tablets,except those prepared by VD,decreased after compression.In summary,the characteristics of the prepared tablets were acquired from their respective powders.

Experimental Investigation of Thermal Performance of Novel Finned Radiators for Automotive Cooling System

This research investigates innovative fin-type radiators for automobile engine cooling system.Micro-channel and helical radiators,along with straight type,were analyzed for heat transfer characteristics under various conditions.The uniqueness of this study is evident in the design of microchannel and helical radiators.For helical radiators,the inner rod features 4/8 helical-shaped water galleries,while the outer tube frame with embedded fins remains consistent.In contrast,the microchannel radiators have compact trapezoidal-shaped water galleries with separate fin strips.Furthermore,the novelty of the research is enhanced by the utilization of 3D printing technology in the manufacturing process.In constant fin height analysis at varied water and air flow rate,Microchannel Water Air Radiator with fin height 10.5 mm(MCWAR10.5)depicted a higher heat transfer rate amongst the radiators.In comparison to Straight Water Air Radiator with fin height 9.5 mm(SWAR9.5),the heat transfer rate is 30.3%and 1.3 times higher.However,in constant fin surface area analysis,microchannel radiator(MCWAR3.2)illustrates lower heat dissipation than Helical radiator(HWAR138)but higher than HWAR134 and Straight radiator(SWAR6).The examination of pumping loss indicated that the Micro-channel radiator outperformed helical radiators due to its lower pressure loss.The average pressure loss for Micro-channel radiators was 0.74 kPa,making it 1.2 times higher than that of a straight radiator(0.62 kPa),indicating a better trade-off.

Designing sodium alloys for dendrite‐free sodium‐metal batteries

Sodium metal,with a high theoretical specific capacity(~1165 mA h g−1)and a low redox potential(−2.71 V vs.SHE)as well as low cost,becomes an attractive option for high‐energy‐density sodium secondary batteries.However,the practical application of sodium metal anodes is hindered by dendrite growth,which results in low energy efficiency,poor lifetime and serious safety issues.To address this challenge,researchers propose various strategies,including the formation of sodium alloys(Na‐M alloys,M=Sn,Sb,Bi,In,etc.)through alloying reaction.The alloying effect has a positive impact in terms of reducing the local current density,mitigating the volume expansion,and inhibiting the dendrite growth.It is thus an effective solution for constructing high‐performance sodium secondary batteries.This review systematically de-scribes the mechanism of dendrite growth and the alloying process of Na‐M alloys,summarizes recent research progress and strategies for applying Na‐M alloys to create dendrite‐free sodium secondary batteries,as well as pre-sents prospects for the development of Na‐M alloys and offers clear sugges-tions for future research.This review aims to inspire further efforts to build dendrite‐free,high‐performance sodium secondary batteries and broaden a new aspect for the next‐generation battery systems.