Risk control of heavy metal in waste incinerator ash by available solidification scenarios in cement production based on waste flow analysis.

Incineration is a common method in municipal solid waste management, which has several advantages such as reducing the volume of waste, but with concerns about exhaust gas and ash management. In this study, heavy metals in bottom ash, secondary furnace ash and fly ash of two waste incinerators in Tehran and Nowshahr were analyzed and its control in cement production was investigated. For this purpose, twelve monthly samples of three types of incinerator ash were analyzed. By combining the studied ashes in the raw materials, the quantity of metals in the cement was analyzed. Finally, by investigating four scenarios based on quantitative variations in the routes of municipal solid waste, ash quantity and the related risk caused by its heavy metals were studied. The results showed that the concentration of heavy metals in the three ash samples of the studied incinerators was 19,513-23,972 µg/g and the composition of the metals included Hg (less than 0.01%), Pb (2.93%), Cd (0.59%), Cu (21.51%), Zn (58.7%), As (less than 0.01%), Cr (15.88%), and Ni (0.91%). The best quality of produced cement included 20% ash and 10% zeolite, which was the basis of the next calculations. It was estimated that the reduction of the release of metals into the environment includes 37 gr/day in best scenario equal to 10.6 tons/year. Ash solidification can be considered as a complementary solution in waste incinerator management.

Determination of metals and BTEX in different components of waterpipe: charcoal, tobacco, smoke and water.

BACKGROUND: The main objective of this study was to evaluate the concentrations of heavy metals and BTEX (benzene, toluene, ethylbenzene and xylene) in smoke and water bowl of 5-most commonly used tobacco brand in waterpipe in Tehran, the capital of Iran. METHODS: Five types of conventional tobacco in Tehran were investigated. Heavy metals and BTEX were analyzed in waterpipe smoke, tobacco, charcoal and water bowl prior to and after smoking by using ICP-OES and GC-MS, respectively. RESULTS: Our results indicated that Khansar and Al Fakher brands had the maximum and minimum concentrations of metals among tobacco consumed, respectively. The results showed that there was a significant difference between content of heavy metals in burned and unburned tobacco. The highest and lowest concentrations of metals were related to Fe and Hg, respectively. CONCLUSION: Results showed that tobacco, charcoal and smoke of waterpipe contained significant contents of toxic metals and BTEX, and exposure to these components could be the main reason for the concerns about waterpipe smoking.

On-chip ion pair-based dispersive liquid-liquid extraction for quantitative determination of histamine H2 receptor antagonist drugs in human urine.

In the present work, an ion-pair based dispersive liquid-liquid microextraction was performed on a centrifugal chip for the first time. The entire DLLME procedure, including flow direction, desperation, and sedimentation of the extracting phase, can be fulfilled automatically on a solitary chip. The chip was made of Poly(methyl methacrylate) (PMMA) and was of two units for two parallel extractions, each consisting of three chambers (for the sample solution, extracting solvents, and sedimentation). As the chip rotated, fluids flowed within the chip, and the dispersion, mixing, extraction, and sedimentation of the final phase were performed on the chip by simply adjusting the spin speed. Determination of two histamine H2 receptor antagonist drugs, cimetidine and ranitidine, as the model analytes from the urine samples was done using the developed on-chip ion-pair based DLLME method followed by an HPLC-UV. The effective parameters on the extraction efficiency of the model analytes were investigated and optimized using the one variable at a time method. Under optimized conditions, the calibration curve was linear in the range of 15-2000 µg L-1 with a coefficient of determination (R2) more than 0.9987. The relative standard deviations (RSD %) for extraction and determination of the analytes were less than 3.7% based on five replicated measurements. LODs less than 10.0 µg L-1 and preconcentration factors higher than 39-fold were obtained for both of the model analytes. The proposed chip enjoys the advantages of both the DLLME method and miniaturization on a centrifugal chip.

Development of a microfluidic-chip system for liquid-phase microextraction based on two immiscible organic solvents for the extraction and preconcentration of some hormonal drugs.

In the present study, for the first time, an on-chip liquid phase microextraction (LPME) coupled with high performance liquid chromatography was introduced for the analysis of levonorgestrel (Levo), dydrogesterone (Dydo) and medroxyprogesterone (Medo) as the model analytes in biological samples. The chip-based LPME set-up was composed of two polymethyl methacrylate (PMMA) plates with microfabricated channels and a microporous membrane sandwiched between them to separate the sample solution and acceptor phase. These channels were used as a flow path for the sample solution and a thin compartment for the acceptor phase, respectively. In this system, two immiscible organic solvents were used as supported liquid membrane (SLM) and acceptor phase, respectively. During extraction, the model analytes in the sample solution were transported through the SLM (n-dodecane) into the acceptor organic solvent (methanol). The new set-up provided effective and reproducible extractions using low volumes of the sample solution. The effective parameters on the extraction efficiency of the model analytes were optimized using one variable at a time method. Under the optimized conditions, the new set-up provided good linearity in the range of 5.0-500µgL(-1) for the model analytes with the coefficients of determination (r(2)) higher than 0.9909. The relative standard deviations (RSDs%) and limits of detection (LODs) values were less than 6.5% (n=5) and 5.0µgL(-1), respectively. The preconcentration factors (PFs) were obtained using 1.0mL of the sample solution and 20.0µL of the acceptor solution higher than 19.9-fold. Finally, the proposed method was successfully applied for the extraction and determination of the model analytes in urine samples.

Simultaneous extraction of acidic and basic drugs via on-chip electromembrane extraction.

In the present work, a on-chip electromembrane extraction (CEME) was designed and employed for simultaneous extraction of mefenamic acid (MEF) and diclofenac (DIC), as acidic model analytes, and betaxolol (BET), as a basic model analyte, followed by HPLC-UV. The CEME consists of two polymethyl methacrylate (PMMA) parts which each part consists of two separated microfluidic channels. A polypropylene sheet membrane impregnated with an organic solvent was sandwiched between the parts. One of the parts was used as the flow path for the sample solution and the other one as holder for the acceptor phases. The separated microfluidic channels of the sample solution part were connected to each other using a small piece of a capillary tube and the sample solution was pumped through them by means of a micro-syringe pump. However, the acceptor phases of the acidic and basic analytes were separately kept stagnant in the two microfluidic channels during the extraction process. A d.c. potential was applied for migration of the analytes from sample solution through the organic membrane into the acceptor phases. All effective variables on the extraction efficiency of the analytes were optimized. Under the optimized conditions, preconcentration factors higher than 15 were achieved and the calibration curves were linear in the range of 10-500 µg L(-1) (r(2) > 0.9982). RSD% values (n = 4) and LODs were less than 7.1% and 5.0 µg L(-1). The results demonstrated that CEME could efficiently be used for the simultaneous analysis of acidic and basic analytes in biological samples.

A novel approach to the consecutive extraction of drugs with different properties via on chip electromembrane extraction.

In the present research, for the first time, a consecutive on chip electromembrane extraction coupled with high performance liquid chromatography was introduced for the analysis of betaxolol (Bet), naltrexone (Nalt) and nalmefene (Nalm) as model analytes with different chemical properties from biological samples. The chip consists of two polymethyl methacrylate (PMMA) parts where two microfluidic channels are carved in each part. These channels were used as a flow path for the sample solution and a thin compartment for the acceptor phase. A porous polypropylene sheet membrane impregnated with an organic solvent was placed between two parts of the chip device in order to separate the channels. Two platinum electrodes were bent at the bottom of these channels that are connected to a power supply providing the electrical driving force for migration of ionized analytes from the sample solution through the porous sheet membrane into the acceptor phase. The new setup provides effective and reproducible extractions by using a low volume of sample solution. Efficient parameters on consecutive electromembrane extraction of the model analytes were optimized by using the one variable at a time method. Under the optimized conditions, the new setup offered a good linearity in the range of 10.0-500 µg L(-1) with coefficient of determination (R(2)) higher than 0.9932. The relative standard deviation (RSD%) and LOD values were less than 6.8% based on four replicate measurements and 10.0 µg L(-1) for the model analytes, respectively. The preconcentration factors higher than 15.6-fold were obtained. Finally, the proposed method was successfully applied for determination and quantification of the model analytes in biological samples.

Dynamic electromembrane extraction: Automated movement of donor and acceptor phases to improve extraction efficiency.

In the present research, dynamic electromembrane extraction (DEME) was introduced for the first time for extraction and determination of ionizable species from different biological matrices. The setup proposed for DEME provides an efficient, stable, and reproducible method to increase extraction efficiency. This setup consists of a piece of hollow fiber mounted inside a glass flow cell by means of two plastics connector tubes. In this dynamic system, an organic solvent is impregnated into the pores of hollow fiber as supported liquid membrane (SLM); an aqueous acceptor solution is repeatedly pumped into the lumen of hollow fiber by a syringe pump whereas a peristaltic pump is used to move sample solution around the mounted hollow fiber into the flow cell. Two platinum electrodes connected to a power supply are used during extractions which are located into the lumen of the hollow fiber and glass flow cell, respectively. The method was applied for extraction of amitriptyline (AMI) and nortriptyline (NOR) as model analytes from biological fluids. Effective parameters on DEME of the model analytes were investigated and optimized. Under optimized conditions, the calibration curves were linear in the range of 2.0-100µgL(-1) with coefficient of determination (r(2)) more than 0.9902 for both of the analytes. The relative standard deviations (RSD %) were less than 8.4% based on four replicate measurements. LODs less than 1.0µgL(-1) were obtained for both AMI and NOR. The preconcentration factors higher than 83-fold were obtained for the extraction of AMI and NOR in various biological samples.

Electrochemical fabrication of electroactive ordered mesoporous electrode.

A novel and simple method for the electrochemical modification of ordered mesoporous silica is described. A well-organized thin film of amine-functionalized ordered mesoporous silica has been deposited electrochemically on the electrode surface. The resulting amine-functionalized electrodes were then subjected to post-functionalization with catechol moieties through electrochemical generation of reactive o-quinone followed by covalent bonding to the anchored amine groups inside the mesoporous channels of silica to afford the corresponding modified electrodes bearing aminocatechol electroactive groups. This simply obtained nanoporous modified electrode with adequate loading of electroactive groups shows very good electrochemical responses.