Performance of Wayne assay for detection of pyrazinamide resistance in Mycobacterium tuberculosis: a meta-analysis study.

Conventional culture-based drug susceptibility testing (DST) of Mycobacterium tuberculosis to pyrazinamide (PZA) is time-consuming and difficult to perform. The current systematic review and meta-analysis was aimed to evaluate the diagnostic accuracy of Wayne assay against culture-based DSTs as the reference standard. We searched the MEDLINE/Pubmed, Embase, and Web of Science databases for the relevant records. The QUADAS-2 tool was used to assess the quality of the studies. Diagnostic accuracy measures (i.e., sensitivity and specificity) were pooled with a random-effects model. Statistical analyses were performed with STATA (version 14, Stata Corporation, College Station, TX, USA), RevMan (version 5.3; The Nordic Cochrane Centre, the Cochrane Collaboration, Copenhagen, Denmark), and Meta-DiSc (version 1.4, Cochrane Colloquium, Barcelona, Spain). A total of 31 articles comprising data for 2457 isolates of M. tuberculosis were included in the final analysis. The pooled sensitivity and specificity of the Wayne assay against all reference tests (the combination of BACTEC MGIT 960, BACTEC 460, and proportion method) were 86.6% (95% CI: 84.3-88.7) and 96.0% (95% CI: 94.8-97). The positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and the area under the curve (AUC) estimates were found to be 17.6 (95% CI: 10.5-29.3), 0.11 (95% CI: 0.06-0.20), 164 (95% CI: 83-320) and 97%, respectively. Deek's test result indicated no evidence for publication bias (P > 0.05). Although the current study shows that the Wayne test is sensitive and specific for detecting PZA resistance, it may be used in combination with conventional DSTs to diagnose PZA resistance accurately.

A supported dendrimer with terminal symmetric primary amine sites for adsorption of salicylic acid.

The aim of this work is to evaluate the uptake of salicylic acid (SA), an emerging pollutant, using a nano-polar dendrimer containing highly branched terminal symmetric amine groups immobilized on mixed-oxide nanoparticles of SiO2-Al2O3. Several variables, including the effect of initial SA concentration, contact time, temperature, initial pH, adsorbent dosage, interfering ions, and the hydrophobicity of the adsorbent (SANP-G1.0) were studied. Because of the electrostatic and hydrogen bonding interactions between SA and the amine functional sites of the nano-polar dendrimer, the adsorbent featured a remarkable SA uptake capacity of over 254.5 mg/g after 5 min contact time. The solution pH had a considerable impact on SA uptake by SANP-G1.0, with optimal uptake occurring around pH 2-5. Kinetic and isotherm studies confirmed that SA removal could be fit with the Sips and pseudo-second-order kinetic models, respectively, implying that a chemical process dominates SA uptake by the SANP-G1.0. The uptake of SA decreased at elevated temperature, demonstrating that this is a chemically and naturally exothermic process between 15 and 80 °C. The uptake efficiency of the reused nanodendrimer was 54% after the tenth adsorption-desorption cycle. Moreover, the SANP-G1.0 showed a high capacity for adsorbing SA from Cayuga Lake water. We studied the possible mechanism of SA uptake, including the effect of interfering ions, using zeta potential, X-ray photoelectron spectroscopy, infrared spectroscopy, and the hydrophobicity of the nanodendrimer. The prepared supported dendrimer, featuring high chemical and mechanical stability, demonstrates good reusability for SA adsorption from aqueous media. An artificial neural network (ANN) model was also designed to simulate SA uptake by SANP-G1.0. The results revealed an excellent fit between the ANN-modeled and experimental data, with a correlation coefficient (R2) of 0.9841.

Identification of tigecycline- and vancomycin-resistant Staphylococcus aureus strains among patients with urinary tract infection in Iran.

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the major causes of hospital- and community-acquired infections worldwide. Although S. aureus rarely accounts for urinary tract infections (UTI), untreated UTI can lead to several complications. For decades vancomycin has been used for the treatment of MRSA infections. This study was performed to assess the in vitro activity of vancomycin, tigecycline, linezolid and quinupristin/dalfopristin against MRSA isolates from UTI patients. Thirty MRSA strains from 54 S. aureus isolates were isolated from patients with UTI. The antimicrobial susceptibility patterns of the strains were determined by the Kirby-Bauer disk diffusion and broth microdilution methods. PCR assays were used to detect the vanA gene. The MRSA isolates resistant to vancomycin were confirmed using the broth microdilution method. The results revealed that the MRSA isolates were 100% susceptible to linezolid and quinupristin/dalfopristin but 93.3% susceptible to vancomycin and tigecycline respectively. The broth microdilution method confirmed two MRSA strains (6.6%) to be resistant to vancomycin and tigecycline. The study identified vancomycin resistance among the MRSA isolates from UTI patients. This vancomycin resistance in MRSA isolates poses a challenge in managing S. aureus infections. Our study's results highlight the need to correctly identify patients in whom last-resort therapy such as linezolid and quinupristin/dalfopristin should be administered.

Adsorption of mercury ions from wastewater by a hyperbranched and multi-functionalized dendrimer modified mixed-oxides nanoparticles.

In this paper, a novel heterogeneous nanodendrimer with generation of G2.0 was prepared by individual grafting of diethylenetriamine, triazine and l-cysteine methyl ester on the modified aluminum-silicate mixed oxides as a potent adsorbent of Hg(II) ions from aqueous media. The prepared nanodendrimer was characterized by nuclear magnetic resonance spectrum (1H NMR and 13C NMR), Fourier transform infrared spectroscopy (FT-IR), Diffuse reflectance UV-Vis spectroscopy (DR UV-Vis), zeta potential (ζ), inductively coupled plasma atomic emission spectroscopy (ICP-AES), transmission electron microscopy (TEM), scanning electron microscopy (SEM), nitrogen adsorption experiments at -196°C and elemental analysis. Equilibrium and kinetic models for Hg(II) ions removal were used by investigating the effect of the contact time, adsorbent dosage, initial Hg(II) ions concentrations, effect of solution's temperature, interfering ions, and initial pH. The contact time to approach equilibrium for higher removal was 6min (3232mgg-1). The removal of Hg(II) ions has been assessed in terms of pseudo-first- and -second-order kinetics, and the Freundlich, Langmuir and Sips isotherms models have also been applied to the equilibrium removal data. The removal kinetics followed the mechanism of the pseudo-second order equation, where the chemical sorption is the rate-limiting step of removal process and not involving mass transfer in solution, which was further proved by several techniques such as zeta potential, FT-IR and DS UV-vis. The thermodynamic parameters (ΔG, ΔH and ΔS) implied that the removal of mercury ions was feasible, spontaneous and chemically exothermic in nature between 15 and 80°C. The nanodendrimer indicated high reusability due to its high removal ability after 15 adsorption-desorption runs. The adsorption mechanisms of Hg(II) ions onto the nanodendrimer was further studied by diverse techniques such as FTIR, EDS, zeta potential, DR UV-Vis spectroscopy and SEM. The possible mechanism of the Hg(II) ions adsorption onto the nanodendrimer could be carried out through the various paths such as electrostatic interaction, complexation, toxic metal chelation and ionic exchange, which eventually resulted in the hydrolysis and precipitation of the adsorbed Hg(II). The l-cysteine methyl ester nanodendrimer could also remove the mercury ions from the Persian Gulf water even after five times of recycling.

Removal of salicylic acid as an emerging contaminant by a polar nano-dendritic adsorbent from aqueous media.

A polar nano-dendritic adsorbent containing amine groups (SAPAMAA) was synthesized onto the nanoparticles of SiO2Al2O3 and its uptake of salicylic acid (SA) from the synthetic and real water was investigated. The synthesized nanomaterials were fully studied by nuclear magnetic resonance spectrum (1H NMR and 13C NMR), Fourier transform infrared spectroscopy (FT-IR), zeta potential (ζ), inductively coupled plasma atomic emission spectroscopy (ICP-AES), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) and elemental analysis. Various parameters such as the effect of the contact time, adsorbent dosage, initial SA concentrations, effect of solution's temperature, interfering ions, the hydrophobicity of the nanoadsorbent and initial pH were assessed. The contact time to approach equilibrium for higher adsorption was 15min (252.8mgg-1). The isotherms could be fitted by Sips model (with the average relative error of 6.6) and the kinetic data could be characterized by pseudo-second-order rate equation (with the average relative error of 13.0), implying chemical adsorption as the ratelimiting step of uptake process which was supported by the experimental data from the effect of interfering ions, zeta potential, and altering of the adsorbent's hydrophobicity. The uptake capacities decreased with temperature increasing, and showed that the uptake of SA was chemically exothermic in nature between 15 and 80°C. In addition, the spent SAPAMAA could be regenerated by the removal of adsorbed SA with NaOH and ethanol to regain the original SAPAMAA, the regenerated SAPAMAA also exhibited the high adsorption capacity after 10 runs. Moreover, SAPAMAA could also be applied to uptake SA from a real water (Anzali lagoon water). We envisage that the prepared nano-dendritic with remarkable characteristics such as environmentally friendly, low-cost, easy preparation in large quantity, high mechanical and chemical stability will play a significant role in developing a new generation of emerging contaminants adsorbent.

Nano modification of NZVI with an aquatic plant Azolla filiculoides to remove Pb(II) and Hg(II) from water: Aging time and mechanism study.

This paper reports the preparation and stabilization of nano zero valent iron (NZVI) on a modified aquatic plant, Azolla filiculoides, and investigates its potential for the adsorption/reduction of Pb(II) and Hg(II) ions from aqueous media even after six months of storage in the lab condition. XRD, TEM and zeta potential results demonstrated that the Azolla-NaOH could be a good stabilizer of aged NZVI (six months) and the green support suppressed the oxidation and aggregation of immobilized NZVI. Kinetic and equilibrium models for lead and mercury ions uptake were developed by considering the effect of the initial Pb(II) and Hg(II) concentrations, contact time, adsorbent dosage, initial pH and effect of temperature. The contact time to obtain equilibrium for maximum uptake by Azolla-OH-NZVI was 20min. The removal of toxic metal ions has been monitored in terms of pseudo-first- and -second-order kinetics, and the Freundlich and Langmuir isotherms models have also been utilized to the equilibrium uptake results. The uptake kinetics followed the mechanism of the pseudo-second-order equation for all systems studied, confirming chemical sorption as the rate-limiting step of adsorption mechanisms and not involving a mass transfer in solution. The thermodynamic results confirmed that the uptake of Pb(II) and Hg(II) ions were feasible, spontaneous and endothermic at 25-80°C. XRD and zeta potential data displayed the existence of Pb(0) and Hg(0) on the Azolla-OH-NZVI surface. The nanobioadsorbent revealed high recyclability due to its reasonable uptake efficiency after 7th adsorption-desorption cycles. The proposed nano biocomposite could also be utilized to uptake Pb(II) and Hg(II) ions from the real water (Anzali lagoon water). However, coated NZVI with Azolla filiculoides as a green and environmentally friendly support suppressed rapid oxidation and aggregation of the immobilized NZVI, therefore vastly enhancing the probability of environmental transport and reducing the sedimentation and potential for toxicity.

Adsorption of methyl orange and salicylic acid on a nano-transition metal composite: Kinetics, thermodynamic and electrochemical studies.

In this work synthesis of Mn-nanoparticles (MnNPs) supported on the Schiff base modified nano-sized SiO2Al2O3 mixed-oxides (Si/Al) and its implementation as an adsorbent for the removal of organic pollutions such as methyl orange (MO) and salicylic acid (SA) was investigated. Si/Al were functionalized by grafting Schiff base ligand and in the next step, MnNPs were prepared over the modified nano sol-gel Si/Al. Structures and adsorption characteristics of the obtained organometallic-modified SiO2/Al2O3 mixed oxide were studied by several methods such as elemental analysis, diffuse reflectance UV-vis spectroscopy, FT-IR spectroscopy, nitrogen adsorption/desorption, scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive X-ray (EDX), inductively coupled plasma (ICP-AES), Electron Paramagnetic Resonance (EPR), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). EPR data of the immobilized manganese ions resulted that the transition state of active sites in the nano-adsorbent are in the form of Mn(II) ions at the surface. The adsorption properties of heterogeneous Mn(II) ions showed that this nano-adsorbent has very good potential to remove MO and SA ions from aqueous solution. The removal efficiency of the SAPAS@MnNPs towards MO reached out to 89.3 and 29.1% and for SA approached to 54.6 and 18.9% at 150 and 500mg/dm(3) initial organic pollution concentrations, respectively. To investigate the adsorption kinetic of Mn(II) ions onto the nano-sized support, pseudo first and pseudo second order kinetics, and the Freundlich, Langmuir and Langmuir-Freundlich isotherm models have also been applied to the equilibrium adsorption data. The contact time to obtain equilibrium for maximum adsorption capacity was 45min. The adsorption process was spontaneous and endothermic in nature and it was well explained with pseudo-second-order kinetic model. No remarkable loss of removal capacity even after 8th times regeneration was obtained, implying that the immobilized MnNPs has high solidity through the regeneration process. Finally, the mechanism of the MO adsorption process as a model has been studied by the CV, EIS and FTIR techniques. The electrochemical results showed that the oxidation of Mn(II) was easier and took place at lower potentials in the presence of MO, where the electron density at SAPAS@MnNP is higher, consequently reduction of Mn(III) to Mn(II) is more favored. These results suggest that the surface of SAPAS@MnNP was interacted and complexed by MO therefore accelerates electron transfer rate of the reaction related to Mn(II)/Mn(III) redox couple.

Enhancement of simultaneous gold and copper recovery from discarded mobile phone PCBs using Bacillus megaterium: RSM based optimization of effective factors and evaluation of their interactions.

Bioleaching of Au from mobile phone printed circuit boards (MPPCBs) was studied, using Bacillus megaterium which is a cyanogenic bacterium. To maximize Au extraction, initial pH, pulp density, and glycine concentration were optimized via response surface methodology (RSM). Bioleaching of Cu, an important inhibitor on Au recovery, was also examined. To maximize Au recovery, the optimal condition suggested by the models was initial pH of 10, pulp density of 8.13g/l, and glycine concentration of 10g/l. Under the optimal condition, approximately 72% of Cu and 65g Au/ton MPPCBs, which is 7 times greater than the recovery from gold mines, was extracted. Cu elimination from the MPPCBs having a rich content of Au did not cause a significant effect on Au recovery. It was found that when the ratio of Cu to Au is high, Cu elimination can considerably improve Au recovery. B. megaterium could extract the total Au from PCBs containing 130g Au/ton MPPCBs.

Removal of BTEX by using a surfactant--Bio originated composite.

The application of ostrich bone waste-loaded a cationic surfactant (OBW-OH-CTABr) bioadsorbent for benzene, toluene, ethylbenzene and p-xylene (BTEX) removal from the synthetic and real waters have been studied, and the prepared biomaterials were studied by Fourier transform infrared (FTIR), X-ray diffraction (XRD), surface area measurements (BET), scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX) and point of zero (pH(PZC)). The immobilization of CTABr molecules on the framework of modified OBW showed good tendency to adsorb BTEX from aqueous solution. The exposure time to obtain equilibrium for maximum removal of BTEX was observed to be 60 min. The removal kinetics of BTEX has been evaluated in terms of pseudo-first- and -second-order kinetics, and the Freundlich and Langmuir isotherm models have also been utilized to the equilibrium removal data. The removal process was spontaneous and endothermic in nature and followed pseudo-second-order kinetic model. The immobilized CTABr showed high reusability because of its high adsorption efficiency after 12th cycles. The proposed low-cost bioadsorbent could also be utilized to adsorb BTEX from the real water (Anzali lagoon water). The OBW-OH-CTABr composite is indeed an attractive biomaterial for drinking water-based pollutants and act as an adsorbent for BTEX and oil spills especially in third world due to its low-cost preparation and regeneration and clean processing of the biomaterial with no byproducts after utilize.

Ferrocene functionalized nanoscale mixed-oxides as a potent phosphate adsorbent from the synthetic and real (Persian Gulf) waters.

The application of covalently attached ferrocene groups to the aluminum-silicate nanoparticles (ASNPs) for phosphate (P) removal from the synthetic and real waters has been studied and the prepared nanomaterials were analyzed by XPS, EDS, BET, TEM, chemical analysis (CHN), FTIR, and ICP-AES. The immobilization of the ferrocene on the surface of the inorganic support (mixed oxides) can lead to reduce the drawback of the pristine ferrocene molecules which may have strong tendency to agglomerate into larger particles, resulting in the negative effect on both available active sites and catalyst performance. XPS of Fe ions evidenced that most of the active sites of the nano-adsorbent is in the form of Fe(III) ions at the surface. The heterogeneous Fe(III) ions were effective toward removal of phosphate. The contact time to obtain equilibrium for maximum adsorption of phosphate (100%) was found to be 120 min. The adsorption kinetics of P has been evaluated in terms of pseudo-first- and -second-order kinetics, and the Freundlich and Langmuir isotherm models have also been tested to the equilibrium adsorption results. The adsorption process was spontaneous and endothermic in nature and followed pseudo-second-order kinetic model. FTIR, EDS and XPS results confirmed the formation of Fe-O-P bond on the Si/Al@Fe surface after adsorption of P from aqueous media. The Si/Al@Fe displayed high reusability due to its high removal capacity after 10th adsorption-desorption runs. The proposed adsorbent could also be utilized to adsorb the P ions from the real sample (Persian Gulf water). The high removal capacity of P ions from the real water and the high levels of reusability confirmed the versatility of the heterogenized ferrocene groups on the ASNPs.

Preparation of iron nanoparticles-loaded Spondias purpurea seed waste as an excellent adsorbent for removal of phosphate from synthetic and natural waters.

The synthesis and characterization of nanoscale zerovalent iron particles (NZVI) supported on Spondias purpurea seed waste (S-NaOH-NZVI) was performed for the adsorption of phosphate (P) ions from waste waters. The effects of various parameters, such as contact time, pH, concentration, reusability and temperature were studied. The adsorption of phosphate ions has been studied in terms of pseudo-first- and -second-order kinetics, and the Freundlich, and Langmuir isotherms models have also been used to the equilibrium adsorption data. The adsorption kinetics followed the mechanism of the pseudo-second-order equation. The thermodynamic parameters (ΔG, ΔH and ΔS) indicated that the adsorption of phosphate ions were feasible, spontaneous and endothermic at 25-80 °C. No significant loss of activity was observed; confirming that the S-NaOH-NZVI has high stability during the adsorption process even after 12th runs. The suggested adsorbent in this paper was also implemented to remove P from the Persian Gulf water. XRD, FTIR and EDX analysis indicated the presence of Fe3 (PO4)2⋅8H2O (vivianite) on the S-NaOH-NZVI@P surface.

Removal of methyl orange on modified ostrich bone waste--a novel organic-inorganic biocomposite.

The synthesis and growth behavior of the chemically modified ostrich bone wastes as bioadsorbents for the removal of methyl orange from aqueous solutions have been investigated. The ostrich bone wastes were treated with cetyltrimethylammonium bromide (CTABr) and sodium dodecyl benzene sulfonate (SDBS). The synthesized biomaterials were characterized by several physicochemical techniques. The modified ostrich bone with CTABr was found to be effective as adsorbent for the removal of methyl orange (MO) from aqueous solutions. The effect of the experimental conditions on the adsorption behavior was studied by varying the contact time, initial MO concentration, temperature, initial pH, chemical modification process, and amount of adsorbent. The contact time to attain equilibrium for maximum adsorption (90%) was found to be 50 min. The adsorption kinetics of MO has been studied in terms of pseudo-first- and -second-order kinetics, and the Freundlich, Langmuir and Langmuir-Freundlich isotherm models have also been applied to the equilibrium adsorption data. The adsorption process was spontaneous and endothermic in nature and followed pseudo-second-order kinetic model.

Enhancement of simultaneous gold and copper extraction from computer printed circuit boards using Bacillus megaterium.

In this research simultaneous gold and copper recovery from computer printed circuit boards (CPCBs) was evaluated using central composite design of response surface methodology (CCD-RSM). To maximize simultaneous metals' extraction from CPCB waste four factors which affected bioleaching were selected to be optimized. A pure culture of Bacillus megaterium, a cyanogenic bacterium, was used to produce cyanide as a leaching agent. Initial pH 10, pulp density 2g/l, particle mesh#100 and glycine concentration 0.5g/l were obtained as optimal conditions. Gold and copper were extracted simultaneously at about 36.81 and 13.26% under optimum conditions, respectively. To decrease the copper effect as an interference agent in the leaching solution, a pretreatment strategy was examined. For this purpose firstly using Acidithiobacillus ferrooxidans copper in the CPCB powder was totally extracted, then the residual sediment was subjected to further experiments for gold recovery by B. megaterium. Using pretreated sample under optimal conditions 63.8% gold was extracted.

Dye removal from aqueous solution by cobalt-nano particles decorated aluminum silicate: kinetic, thermodynamic and mechanism studies.

This article describes the preparation of a nanoadsorbent containing Co-nanoparticles decorated functionalized SiO2-Al2O3 mixed-oxides as a scavenger toward removal of methyl orange. SiO2-Al2O3 mixed-oxides were functionalized with pyridine-2-carbaldehyde and thereafter, in the next step, Co-nanoparticle was prepared over the modified mixed-oxides. The as-prepared nanoadsorbent was characterized by Fourier transform infrared (FTIR), UV-visible diffuse reflectance spectra (UV-vis DRS), inductively coupled plasma atomic emission spectroscopy (ICP-AES), Brunauer-Emmett-Teller (BET), transmission electron microscopy (TEM), electron paramagnetic resonance (EPR), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Results showed that Co-nanoparticle with average size of about 5-25 nm was immobilized successfully on the surface of modified mixed-oxides and was widely dispersed. EPR and CV of Si/Al-PAEA=PyCA@CoNP confirmed that most of the covalently bond active sites of the nano-adsorbent are in the form of Co(II) ions. The supported cobalt is a suitable and efficient adsorbent for the removal of methyl orange from aqueous solution. The heterogeneous Co-NPs were found to be effective adsorbent for the removal of methyl orange ions from solution. The adsorption process was spontaneous and endothermic in nature and followed pseudo-second-order kinetic model. The CV and EIS of the Co-NPs-MO indicates an easily oxidizable environment, this being in agreement with the FTIR data, where the electron density at Co-NPs is higher due to the presence of a donor-electron ligand (methyl orange), that is, reduction of Co-NPs from +3 to +2 oxidation state is more favored.

Synthesis and adsorption characteristics of an heterogenized manganese nanoadsorbent towards methyl orange.

Heterogeneous Mn nanoparticles (5-30 nm diameter) is found to be a nanomaterial for the rapid removal of large quantities of toxic dye (methyl orange) from aqueous solution, with wide ranging potential applications. The synthesized materials were characterized with different methods such as FT-IR spectroscopy, CHN elemental analysis, BET, SEM, TEM, ICP-OES and EPR. The contact time to obtain equilibrium for maximum adsorption of methyl orange was 20 min. EPR of Mn ions evidenced that most of the covalently bond active sites of the nano-adsorbent are in the form of Mn(III) ions at the surface. The heterogeneous Mn(III)-Cl ions were found to be effective adsorbent for the removal of methyl orange from solution. The adsorption of methyl orange ions has been studied in terms of pseudo-first-order and pseudo-second-order kinetics, and the Freundlich, Langmuir and Langmuir-Freundlich isotherm models have also been applied to the equilibrium adsorption data. The adsorption process was spontaneous and endothermic in nature and followed pseudo-second-order kinetic model.

Simultaneous recovery of Ni and Cu from computer-printed circuit boards using bioleaching: statistical evaluation and optimization.

Computer printed circuit boards (CPCBs) have a rich metal content and are produced in high volume, making them an important component of electronic waste. The present study used a pure culture of Acidithiobacillus ferrooxidans to leach Cu and Ni from CPCBs waste. The adaptation phase began at 1g/l CPCBs powder with 10% inoculation and final pulp density was reached at 20g/l after about 80d. Four effective factors including initial pH, particle size, pulp density, and initial Fe(3+) concentration were optimized to achieve maximum simultaneous recovery of Cu and Ni. Their interactions were also identified using central composite design in response surface methodology. The suggested optimal conditions were initial pH 3, initial Fe(3+) 8.4g/l, pulp density 20g/l and particle size 95µm. Nearly 100% of Cu and Ni were simultaneously recovered under optimum conditions. Finally, bacterial growth characteristics versus time at optimum conditions were plotted.

Nanoscale Zero-Valent Iron (NZVI) supported on sineguelas waste for Pb(II) removal from aqueous solution: kinetics, thermodynamic and mechanism.

In this study, the synthesis and characterization of a new adsorbent containing nanoscale zerovalent iron particles (NZVI) decorated sineguelas waste (S-NaOH-NZVI) from agriculture biomass was investigated for the adsorption/reduction of inorganic pollution such as Pb(II) ions. The combination of ZVI particles on the surface of sineguelas waste can help to overcome the disadvantage of ultra-fine powders which may have strong tendency to agglomerate into larger particles, resulting in an adverse effect on both effective surface area and catalyst performance. The synthesized materials were characterized with different methods such as FT-IR, BET, XRD, TEM and pHPZC. Good dispersion of NZVI particles (ca. 10-70nm) on the sineguelas waste was observed. The effects of various parameters, such as contact time, pH, concentration, adsorbent dosage and temperature were studied. The adsorption of Pb(II) ions has been studied in terms of pseudo-first- and second-order kinetics, and the Freundlich, Langmuir and Langmuir-Freundlich isotherms models have also been used to the equilibrium adsorption data. The adsorption kinetics followed the mechanism of the pseudo-second-order equation. The thermodynamic parameters (ΔG, ΔH and ΔS) indicated that the adsorption of Pb(II) ions were feasible, spontaneous and endothermic at 25-80°C. XRD analysis indicated the presence of Pb(0) on the S-NaOH-NZVI surface. This study suggests that the modified sineguelas waste by NZVI particles can be prepared at low cost and the materials are environmentally benign for the removal of Pb(II) ions, and likely many other heavy metal ions, from water.

Kinetic and thermodynamic investigations of Pb(II) and Cd(II) adsorption on nanoscale organo-functionalized SiO2-Al2O3.

This paper reports the preparation of three new Schiff base ligands modified SiO2-Al2O3 mixed oxide adsorbents, and their use for removal of Pb(II) and Cd(II) from aqueous solutions. Equilibrium and kinetic models for Pb(II) and Cd(II) sorption were applied by considering the effect of the contact time, initial Pb(II) and Cd(II) concentrations, effect of temperature, and initial pH. The contact time to attain equilibrium for maximum adsorption was 120 min. These heterogeneous Schiff base ligands were found to be effective adsorbents for the removal of heavy metal ions from solution, with Si/Al-pr-NH-et-N=pyridine-2-carbaldehyde having a high adsorption capacity for Pb(II) and Cd(II) ions from aqueous solution. The adsorption of heavy metal ions has been studied in terms of pseudo-first- and -second-order kinetics, and the Freundlich, Langmuir and Langmuir-Freundlich isotherms models have also been used to the equilibrium adsorption data. The adsorption kinetics followed the mechanism of the pseudo-second-order equation for all systems studied, confirming chemical sorption as the rate-limiting step of adsorption mechanisms and not involving mass transfer in solution, which were confirmed by techniques of DS UV-vis and FT-IR. The thermodynamic parameters (ΔG, ΔH and ΔS) indicated that the adsorption of Pb(II) and Cd(II) ions were feasible, spontaneous and endothermic between 25 and 80°C.

Determination of the pesticide naptalam and its degradation products by positive and negative ion mass spectrometry.

N-1-Naphthylphtalamic acid (naptalam) and its degradation products, 1-naphthylamine and N-(1-naphthyl) phthalimide were simultaneously determined in river water by two independent mass spectrometric (MS) methods. These were negative ion MS (NIMS) and programmable temperature vaporizer gas chromatography mass spectrometry (PTV-GC MS) with electron impact ionization (positive ions). Prior to the NIMS analysis, the samples were preconcentrated by solid phase extraction (SPE) of C18 membrane discs. The PTV-GC MS studies were performed without any preconcentration procedure. Selected ion monitoring (SIM) and internal standardization with naphthalene were applied in both methods. The limits of determination (LOD) of NIMS studies were 230, 270 and 260 ng L-1 for naptalam, 1-naphthylamine and N-(1-naphthyl) phthalimide, respectively, with relative standard deviation (RSD) < 1% (n = 5) and of PTV-GC MS 17, 11 and 15 ng L-1 (RSD < 0.7%, n = 5). The LOD, linearity, RSD and time required for these methods are far better than for HPLC analyses.

The foot-and-mouth disease situation in Iran.

Foot-and-mouth disease has been known in Iran since long ago. Typing of virus was done in 1950 at Mérieux Institute and since 1959 at Razi Institute. Type Asia 1 was isolated three times: in 1957, in 1964 and in 1973. In June 1962, FMD type SAT 1 entered Middle-Eastern countries; it was soon controlled, and completely eradicated by the end of 1963. At the present time, endemic types of FMD cause limited and sporadic outbreaks in some regions of Iran; their incidence is lowered every year. Except the endemic types A and O, all other types in Iran are considered as exotic. The control measures are: 1) stamping-out policy against exotic types, 2) mass-vaccination of all healthy susceptible animals by a polyvalent vaccine, 3) regular disinfection of premises and utensils, 4) strict application of sanitary measures.