GC column effluent splitter for problematic solvents introduced in large volumes: Determination of di-(2-ethylhexyl) phthalate in triglyceride matrices as an application

Introduction of solutions of up to several milliliters by on-column injection of large volumes or by coupled HPLC-GC may cause problems with GC detectors (FID, AFID, MS). For instance, dichloromethane forms large amounts of hydrochloric acid and carbon black in FIDs. A column effluent splitter was developed for keeping the major portion of the solvent vapors away from the detector; approximately 99% of the vapor is vented while the remaining 1% of vapor is used for detecting the widths of the solvent peaks. During analysis, the split ratio is reversed by a strong increase of the resistance to the gas flow through the split exit line. The system was used for the determination of di-(2-ethylhexyl)-phthalate (DEHP) in triglyceride matrices of various foods. Direct determination by HPLC is not sufficiently sensitive, whereas direct analysis by GC is hindered by the triglycerides. Solutions of fats or oils were pre-separated on a silica column using dichloro-methanelcyclohexane 1:l with addition of 0.05 % acetonitrile as eluent. The HPLC fraction containing the DEHP was transferred to GC through a loop-type interface using concurrent solvent evaporation. Detection limits were around 0.1 ppm.     

大口径、长焦距平行光管装调技术研究

主要以焦距7500mm、口径750mm的大型牛顿式平行光管的装调与标定方法为研究对象。该平行光管作为某空间光学系统的检测与标定基准,因此对其装调后的像质稳定性、出射光束平行性、口径对称性、出射光束水平性等参数都提出了极高的要求。从平行光管的关键指标参数要求出发,归纳了Φ750mm平行光管进行初步装调,再研究精密装调的技术原理和方案,分析了可能存在的失调量、产生原因与对应的调整方法。介绍了干涉辅助装调的实验过程和其中遇到的问题与解决方法,最终得到了满足技术要求的装调结果。     

Dephenolization,dearomatization and detoxification of olive mill wastewater with sonication combined with additives and radical scavengers

In this study, the effects of some additives [manganese (III) oxide (Mn₃O₄), Cu⁺², Fe⁰ and potassium iodate (KIO₃)] and some radical scavengers [sodium carbonate (Na₂CO₃), perfluorohexane (C₆F₁₄) and t-butyl alcohol (C₄H₁₀O)] on the sonication of olive mill effluent wastewater (OMW) were investigated since the wastewaters of this industry are removed with low efficiencies. The maximum total phenol and total aromatic amines (TAAs) removal efficiencies were 88% and 79%, respectively, at 60 °C with only 150 min sonication. The maximum phenol removal was found as 98% with 19 mg L⁻¹ perfluorohexane and 5 mg L⁻¹ Fe⁰ while the maximum TAAs removal was 99% with 16 mg L⁻¹ KIO₃. Catechol, tyrosol, quercetin, caffeic acid, 4-methyl catechol, 2-phenylphenol (2-PHE) and 3-phenyl phenol (3-PHE) were detected as phenol intermediates while trimethlyaniline, aniline, o-toluidine, o-anisidine, dimethylaniline, ethylbenzene and durene were identified as TAAs in the OMW. The maximum acute toxicity removals were 96% and 99% in Vibrio fischeri and Daphnia magna, respectively. Total phenol, TAAs and the toxicity in an OMW were removed efficiently and cost-effectively through sonication.     

Study of deposition patterns of plating layers in SiC/Cu composites by electro-brush plating

SiC reinforced copper composite coatings were prepared by electro-brush plating with micron-size silicon carbide (SiC) ranging from 1 to 5 μm on pure copper sheet in this paper. The micro-structural characterizations of SiC/Cu composite coatings were performed by optical microscope and Scanning Electron Microscope (SEM) coupled with spectrometer, to study co-deposition mechanism of SiC/Cu. It was found that there were three different patterns of SiC deposition in plating layers during electro-brush plating process, i.e. the particles could deposit inside copper grains, in grain boundaries, or in holes of the surface. To investigate deposition mechanism of each pattern, size of SiC and copper grains was compared. By comparison of size of copper grains and hard particles, SiC were either wrapped in copper grains or deposited in grain boundaries. Moreover, electro-brush plating layers at different brush velocities and current densities were obtained respectively, to analyze the microstructure evolution of the composite coatings. The hardness of plating layers was measured. The results indicated at the current density of 3 A/dm², the SiC/Cu coating was compact with SiC content at a high level and the hardness reached a maximum.     

Role of H2O2 in the fluctuating patterns of COD (chemical oxygen demand) during the treatment of palm oil mill effluent (POME) using pilot scale triple frequency ultrasound cavitation reactor

Palm oil mill effluent (POME) is a highly contaminating wastewater due to its high chemical oxygen demand (COD) and biochemical oxygen demand (BOD). Conventional treatment methods require longer residence time (10–15 days) and higher operating cost. Owing to this, finding a suitable and efficient method for the treatment of POME is crucial. In this investigation, ultrasound cavitation technology has been used as an alternative technique to treat POME. Cavitation is the phenomenon of formation, growth and collapse of bubbles in a liquid. The end process of collapse leads to intense conditions of temperature and pressure and shock waves which assist various physical and chemical transformations. Two different ultrasound systems i.e. ultrasonic bath (37 kHz) and a hexagonal triple frequency ultrasonic reactor (28, 40 and 70 kHz) of 15 L have been used. The results showed a fluctuating COD pattern (in between 45,000 and 60,000 mg/L) while using ultrasound bath alone, whereas a non-fluctuating COD pattern with a final COD of 27,000 mg/L was achieved when hydrogen peroxide was introduced. Similarly for the triple frequency ultrasound reactor, coupling all the three frequencies resulted into a final COD of 41,300 mg/L compared to any other individual or combination of two frequencies. With the possibility of larger and continuous ultrasonic cavitational reactors, it is believed that this could be a promising and a fruitful green process engineering technique for the treatment of POME.     

Determination of metal ions extracted by DTPA in a soil treated with effluent using an Hg-electroplated-Pt microelectrode

Determinations of Cu, Fe, Mn and Zn were performed in an oxisol soil treated with effluent originated from a biodigester septic cesspool. The extracts were obtained from a DTPA/TEA (pH 7.3) solution and analysed by electroanalytical methodologies using square wave anodic stripping voltammetry (SWASV) for the analysis of Cu, Mn and Zn and square wave voltammetry (SWV) for Fe analysis, both of them with a thin mercury film microelectrode (ME-Hg). DTPA (diethylenetriaminepentaacetic acid) complexes with Cu, Mn and Fe show electroactivity in the potentials range close to the ones for the free ions in solution, but the Zn complex did not show any electroactivity at the potential range analysed. SWASV/ME-Hg and SWV/ME-Hg results were in good agreement (r² = 0.996) with the flame atomic absorption spectroscopy (FAAS) analyses, demonstrating that electroanalytical methodologies can be used for micronutrient determinations in soil extracts without serious interferences of the matrix components. Some characteristics of the complex formed between DTPA-metals are explored by EPR experiments.     

Decolorization of Distillery Effluent Using Poly(Vinyl Chloride) and Cellulose Acetate Phthalate as Adsorbents

Decolorization of distillery effluents, using low cost polymer adsorbents, is one of the challenging areas for environmental technologists. Untreated distillery effluents are harmful to the environment, causing foul smell, spoiling fresh water sources and killing aquatic life. The color of distillery effluents have been decolorized by using polymer based adsorbents, such as poly(vinyl chloride) (PVC) and cellulose acetate phthalate (CAP), which are water insoluble, easily available, and cheap. In the present article, special emphasis is given to studies such as the effect of contact time, dosage amount, dilution, and the variation in the amount of sample on the degree of decolorization of the effluent. The decolorization of a distillery effluent was monitored by using UV/Visible spectroscopy and Fourier transform infrared spectroscopy (FTIR). From these studies, it was noticed that moderate to fair results were obtained and it was also found that CAP was a better adsorbent, compared to PVC, for decolorization of distillery effluents.     

阴离子对城市污水二级出水DOM光谱特性影响

利用三维荧光光谱法和紫外光谱法,研究阴离子对城市污水二级出水DOM光谱的影响,为环境中DOM分析提供数据基础。结果表明：投加SO2-₄和Cl-使二级出水DOM荧光峰强度小幅度增强或降低。投加NO-₃浓度在0.005～0.1 mol·L-1时,出现代表可见光区类腐殖质的荧光峰。随投加NO-₃浓度增大,荧光强度显著降低;代表类腐殖质荧光峰的激发波长和发射波长与紫外吸收峰右侧红移。NO-₃投加浓度与HIX,UV₂₅₄,UV₂₅₃/UV₂₀₃,α₃₀₀和α₂₅₀/α₃₆₅呈较强的正相关性,决定系数分别为0.993,0.994,0.987,0.998和0.995;与BIX呈负相关性,R2为0.949;对α₃₅₀和α₃₅₅影响不大。结果表明,投加SO2-₄和Cl-对二级出水DOM的荧光(除荧光强度外)和紫外特性影响较小。样品NO-₃浓度不同时,用荧光参数和紫外参数衡量不同DOM来源和性质时将产生一定影响。     

Effects of Impregnated Amidophosphonate Ligand Concentration on the Uranium Extraction Behavior of Mesoporous Silica

A series of solid-phase uranium extractants were prepared by post-synthesis impregnation of a mesoporous silica support previously functionalized with octyl chains by direct silanization. Five materials were synthesized with 0, 0.2, 0.3, 0.4 and 0.5 mmol of the amidophosphonate ligand DEHCEBP per gram of functionalized solid, and the effect of the ligand concentration on the uranium extraction efficiency and selectivity of the materials was investigated. Nitrogen adsorption–desorption data show that with increasing ligand loadings, the specific surface area and average pore volume decrease as the amidophosphonate ligand fills first the micropores and then the mesopores of the support. Acidic uranium solutions with a high sulfate content were used to replicate the conditions in ore treatment leaching solutions. Considering the extraction kinetics, the equilibration time was found to increase with the ligand concentration, which can be explained by the clogging of micropores and the multilayer arrangement of the DEHCEBP molecules in the materials with their highest ligand contents. The fact that the equilibrium ligand/uranium ratio is about 2 mol/mol regardless of the ligand concentration in the material suggests that all the ligand molecules remain accessible for extraction. The maximum uranium extraction capacities ranged from 30 mg∙g⁻¹ at 0.2 mmol∙g⁻¹ DEHCEBP to 54 mg∙g⁻¹ in the material with 0.5 mmol∙g⁻¹ DEHCEBP. These materials could therefore potentially be used as solid-phase uranium extractants in acidic solutions with high sulfate concentrations.     

Synthesising injectable molecular self-curing polymer from monomer derived from lignocellulosic oil palm empty fruit bunch biomass: A review on treating Osteoarthritis

Osteoarthritis (OA) is a chronic and irreversible degenerative joint disease that most commonly affects individuals in their forties and fifties worldwide due to the continuously increasing life expectancy. Although joint replacement is an effective remedy for severe end-stage OA, the functional outcomes could be unsatisfactory, while the implants might have a limited lifespan. Due to the drawbacks and limitations of the joint replacement approach, bone Tissue Engineering (TE) is one of the promising bone tissue regeneration technologies that aid in cartilage repair and regeneration and has attracted the attention of experts. The advanced development of biopolymers, in particular biopolymer derived from Oil Palm Empty Fruit Bunch (OPEFB), has been utilised in the fabrication of scaffolds that serve as a crucial component in bone TE. The abundant supply of OPEFB biomass and the increasing trend of converting waste into wealth for environmental sustainability have also provided the opportunity and interest to fully apply biopolymer-derived materials for bone scaffolding and other applications. Therefore, this paper aimed to provide a review of the biopolymers derived from OPEFB for the treatment of OA and other related applications. A brief overview of the biomass sources in Malaysia was presented, followed by a discussion on the chemical compositions and pre-treatment methods of OPEFB by using organosolv pre-treatment and enzymatic hydrolysis for maximum glucose recovery, monomer derived from cellulose OPEFB and synthesizing self-curing polymer scaffold. Additionally, a detailed review of the polymeric biomaterials in bone TE for the fabrication of scaffolds were included in this review. Most importantly, the paper described the potential use of injectable polymeric biomaterials that provide a significant benefit in orthopaedic applications. Overall, this paper provides a perspective on the potential of OPEFB-derived injectable scaffolds as an alternative OA treatment and future bone TE applications.