Synthesis and application of Ce-doped TiO2 nanoparticles loaded on activated carbon for ultrasound-assisted adsorption of Basic Red 46 dye.

Ce was doped on TiO2 nanoparticles (NPs), and this association was loaded on activated carbon (Ce-TiO2-NPs-AC). The characterization was completed by FE-SEM, TEM, and XRD, and finally these NPs were used for the ultrasonic-assisted adsorption of Basic Red 46 (BR 46) from aqueous solution. An experimental model suggested by the central composite design (CCD)-as a branch of response surface methodology (RSM)-provides insight into the influence of variables, such as BR 46 concentration, pH, adsorbent mass, and sonication time, on BR 46 removal. Experimental results revealed that setting conditions at 25 mg L-1 of BR 46, pH 5.0, 0.02 g of Ce-TiO2-NPs-AC and 4 min sonication resulted in a high coefficient of determination (R2 > 0.99) and low probability values. The difference in the values is likely due to the accumulation of more than 99% of BR 46, while equilibrium data described by Langmuir isotherm model with a high adsorption capacity of 58.61 mg g-1 and adsorption process were successfully correlated with pseudo-second-order kinetics model.

Ultrasound wave assisted adsorption of congo red using gold-magnetic nanocomposite loaded on activated carbon: Optimization of process parameters.

In this study, gold-magnetic nanocomposite in the presence of ultrasound wave assisted was synthesized and loaded on activated carbon (Au-Fe3O4-NCs-AC) by simple, fast and low-cost process. This novel material was applied for ultrasound assisted adsorption of congo red (CR) as model of toxic and even carcinogenic substance from aqueous solution. The detail of morphology and identity of Au-Fe3O4-AC was characterized by SEM and TEM techniques and correlation among response to variables such as pH (2-10), adsorbent mass (0.005-0.025 g), initial CR concentration (10-30 mg L-1) and ultrasound time (2-6 min) was investigated by response surface methodology (RSM) under central composite design (CCD). Analysis of variance (ANOVA) exhibit a high R2 value of 0.999 and confirm suitability of constructed second-order regression model for excellent evaluation and prediction of the experimental data. The interaction and main factor and optimum conditions of the under study process were determined from response surface plots based on desirability function. The maximum CR adsorption were achieved at pH of 4, 15 mg L-1 of CR, 0.017 g of Au-Fe3O4-AC and 5 min sonication which owing to 99.49% removal efficiency is highly recommended for future CR removal from different matrixes. Adsorption kinetic follow second-order rate expression in combination to inter particle diffusion and equilibrium adsorption data best represented by the Langmuir isotherm with maximum mono-layer adsorption capacity of 43.88 mg g-1.

Optimization of process parameters for determination of trace Hazardous dyes from industrial wastewaters based on nanostructures materials under ultrasound energy.

In this study, ultrasound-assisted dispersive solid phase micro-extraction based on nanosorbent namely silver-zinc oxide nanoparticles loaded on activated carbon (Ag-ZnO-NP-AC) combined with derivative spectrophotometry method for the simultaneous pre-concentration and determination of Methyl Green (MG) and Rose Bengal (RB) dyes in water and industrial wastewater. Characterized sorbent by field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), particle-size distribution (PSD), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD) and Transmission electron microscopy (TEM) analysis with superior adsorption capacity was applied in ultrasound assisted dispersive-solid-phase micro-extraction (UA-DSPME) methodology. pH, sorbent mass, ultrasonication time, and eluent volume influence and contribution on response correspond to simultaneous pre-concentration and determination of MG and RB were optimized by response surface methodology (RSM) and results were compared with the experimental values. Under the optimal conditions (UA-DSPME), the enrichment factors (EFs) were 93.89 and 97.33 for the MG and RB dyes, respectively. The limits of detection were 2.14 and 2.73ngmL-1 and the limit of quantification were 7.15 and 9.09ngmL-1 for MG and RB, respectively. The analytes can be determined over 10-2000ngmL-1 with recoveries between 90.8% to 97.7% and RSDs less than 3.6%. The developed method due to simplicity and rapidity is able successful for repeatable and accurate monitoring of under study analytes from complicated matrices.

Synthesis of nanocomposites of iron oxide/gold (Fe3O4/Au) loaded on activated carbon and their application in water treatment by using sonochemistry: Optimization study.

This paper focuses on the finding best operational conditions using response surface methodology (RSM) for Rhodamine123 (R123) and Disulfine blue (DSB) dyes removal by ultrasound assisted adsorption onto Au-Fe3O4 nanoparticles loaded on activated carbon (Au-Fe3O4 NPs-AC). The influences of variables such as initial R123 (X1) and DSB concentration (X2), pH (X3), adsorbent mass (X4) and sonication time (X5) on their removal were investigated by small central composite design (CCD) under response surface methodology. The significant variables and the possible interactions among variables were investigated and estimated accordingly. The best conditions were set as: 4min, 4.0, 0.025g, 13.5 and 26.5mgL-1 for sonication time, pH, adsorbent weight, initial R123 and DSB concentration, respectively. At above conditions, the adsorption equilibrium and kinetic follow the Langmuir isotherm and pseudo-second-order kinetic model, respectively. The maximum monolayer capacity (Qmax) of 71.46 and 76.38mgg-1 for R123 and DSB show sufficiency of model for well presentation of experimental data.

Nanocomposites: Synthesis, characterization and its application to removal azo dyes using ultrasonic assisted method: Modeling and optimization.

S-doped and Cu- and Co-doped TiO2 was synthesized by a sol-gel method and characterized by FE-SEM, XRD, EDX and FTIR. The Co/Cu/S-TiO2 nanocomposite loaded on the activated carbon as new nanoadsorbent was used for simultaneous removal of methylene blue (MB) and sunset yellow (SY) from aqueous solution by ultrasonic-assisted adsorption method. In this work, central composite design (CCD) and adaptive neuro-fuzzy inference system (ANFIS) as a support tool for examining data and making prediction are used to recognize and predict the removal percentage in MB and SY dye solution of different concentrations. The predictive capabilities of CCD and ANFIS are compared in terms of square correlation coefficient (R2), root mean square error (RMSE), mean absolute error (MAE) and absolute average deviation (AAD) against the empirical data. It is found that the ANFIS model shows the better prediction accuracy than the CCD model. In addition to, the optimization of ultrasound-assisted simultaneous removal of methylene blue (MB) and sunset yellow (SY) on the Co/Cu/S-TiO2/AC nanocomposite by response surface methodology (RSM) for the optimization of the process variables, such as MB and SY concentrations, Co/Cu/S-TiO2/AC nanocomposite dose and sonication time, was investigated. Various isotherm and kinetic models were used in the experimental data. The results revealed that the langmuir isotherm and pseudo-second-order model had a better correlation than the other models.

Synthesis of ZnO-nanorod-based materials for antibacterial, antifungal activities, DNA cleavage and efficient ultrasound-assisted dyes adsorption.

Undoped and Au-doped ZnO-nanorods were synthesized in the presence of ultrasound and loaded on activated carbon following characterization by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmittance electron microscopy (TEM), UV-vis spectrophotometry and Fourier transform infrared spectroscopy (FTIR). The Au-doped ZnO-nanorod-loaded activated carbon (Au-ZnO-NRs-AC) was used for the simultaneous removal of methylene blue (MB) and auramine O (AO) from aqueous solutions. Central composite design (CCD) under response surface methodology (RSM) was applied to model and optimize the dyes removal versus adsorbent mass, pH, and initial dyes concentration and sonication time as well as to investigate the possible interaction between these variables. The optimum values of the initial MB and AO dyes concentration, adsorbent mass, pH and sonication time were found to be 12 and 10mgL-1, 0.0124g, 6.4, and 4min respectively. The rapid adsorption process at neutral pH using very small amount of the adsorbent makes it promising for the wastewater treatment applications. More than 99.5% of both dyes was removed with maximum adsorption capacities in binary-component system (107.5 and 95.7mgg-1 for MB and AO, respectively). The kinetics and isotherm studies showed that the second-order and Langmuir models apply for the kinetics and isotherm of the adsorption of MB and AO on the adsorbent used here. Moreover, the wastewater treatment by using an antibacterial/antifungal adsorbent makes the process much more valuable. Therefore, additional studies were performed which showed efficient antibacterial/antifungal activities and DNA cleavage of undoped and Au-doped ZnO nanorods as constituent of the adsorbent applied here.

Comparing Characteristics of Early-Onset Injection Drug Users to Those With Late-Onset Injection in Kermanshah, Iran.

BACKGROUND: Characteristics and behaviors of early-onset injection drug users are under studied topics in Iran. This study aimed to identify and compare the demographic characteristics as well as the drug using behaviors of early-onset and late-onset injection drug users in Kermanshah, West Iran. METHODS: In this cross-sectional study using snowball and convenience sampling, we recruited 450 people during the Fall of 2014 from two drop in centers in Kermanshah, Iran. We collected data through face-to-face interviews. Early-onset injection is defined as whether the person reported their first injection at 22 years of age or younger. Subsequently, late-onset injection is defined as 23 years of age or older. We compared the characteristics of the two groups through both univariate and multiple logistic analyses. RESULTS: Overall, 54% (CI 95%: 44.3%, 62.2%) were early injectors. After controlling for low socioeconomic status, initiation of drug use at a young age, multiple drug use and methamphetamine use were all significantly associated with a higher likelihood of early-onset injection. Additionally, early-onset injection was associated with recent syringe borrowing (OR = 2.6, p = 0.001), recent syringe lending (OR = 1.4, p = 0.01), recent cooker sharing (OR = 3.2, p = 0.01) and injecting two or more times a day (OR = 2.2, p = 0.04). CONCLUSION: Early-onset injectors were more likely to report a lower socioeconomic status, initiation of first drug use at a younger age, using methamphetamine alongside polydrug use, and engaging in higher risk taking behaviors like borrowing needles. With these associations, the study emphasizes the need for drug-prevention programs to focus on the transition to injection drug use at younger ages.

HIV Risk Perception and Risky Behavior Among People Who Inject Drugs in Kermanshah, Western Iran.

PURPOSE: Understanding and increasing awareness on individual risk for HIV infection as well as HIV risk perception's effects on different behavioral outcomes for people who inject drugs (PWID) is important for policymaking and planning purposes. The objectives of the present study were to determine whether HIV risk perception was associated with greater injection and sexual risk-taking behaviors among PWIDs. METHOD: We surveyed 460 PWID in Kermanshah regarding their demographic characteristics, sexual risk behaviors, HIV risk perception, and drug-related risk behaviors in the month prior to the study. Three classes of HIV risk perception were identified using ordinal regression to determine factors associated with HIV risk perception. RESULTS: Study participants were categorized as follows: "low" (n = 100, 22%), "moderate" (n = 150, 32%), and "high" (n = 210, 46%) risk perception for becoming infected with HIV. The odds of categorizing as "high" risk for HIV was significantly greater in PWID that reported unprotected sex (adjusted odds ratio (AOR) 2.4, p value 0.02), receptive syringe sharing (AOR 1.8, p value 0.01), and multiple sex partners (AOR 1.4, p value 0.03). PWID who reported unprotected sex had 2.7 times the odds of "high" risk perception when compared to PWID with "low" risk perception. CONCLUSION: Findings show that PWID could rate their HIV risk with acceptable accuracy. Additionally, perceived HIV risk was associated with many risk factors for transmission of HIV, emphasizing the importance of developing targeted prevention and harm reduction programs for all domains of risk behaviors, both sexual and drug-related use.

Comparative study on ultrasonic assisted adsorption of dyes from single system onto Fe3O4 magnetite nanoparticles loaded on activated carbon: Experimental design methodology.

The present study the ultrasound assisted adsorption of dyes in single system onto Fe3O4 magnetite nanoparticles loaded on activated carbon (Fe3O4-MNPs-AC) was described following characterization and identification of this adsorbent by conventional techniques likes field emission scanning electron microscopy, transmission electron microscopy, particle-size distribution, X-ray diffraction and Fourier transform infrared spectroscopy. A central composite design in conjunction with a response surface methodology according to f-test and t-test for recognition and judgment about significant term led to construction of quadratic model which represent relation among responses and effective terms. This model has unique ability to predict adsorption data behavior over a large space around central and optimum point. Accordingly Optimum conditions for well and quantitative removal of present dyes was obtained best operation and conditions: initial SY, MB and EB dyes concentration of 15, 15 and 25mgL-1, 4.0, 6.0 and 5.0 of pH, 360, 360 and 240s sonication time and 0.04, 0.03 and 0.032g of Fe3O4-MNPs-AC. Replication of similar experiment (N=5) guide that average removal percentage of SY, MB and EB were found to be 96.63±2.86%, 98.12±1.67% and 99.65±1.21% respectively. Good agreement and closeness of Predicted and experimental result and high adsorption capacity of dyes in short time strongly confirm high suitability of present method for waste water treatment, while easy separation of present nanoparticle and its good regeneration all support good applicability of Fe3O4-MNPs-AC for waste water treatment. The kinetic study can be represented by combination of pseudo second-order and intraparticle diffusion. The obtained maximum adsorption capacities correspond to Langmuir as best model for representation of experimental data correspond to dyes adsorption onto Fe3O4-MNPs-AC were 76.37, 78.76 and 102.00mgg-1 for SY, MB and EB, respectively. In addition, the performance comparison of ultrasound-assisted, magnetic stirrer assisted and vortex assisted adsorption methods demonstrates that ultrasound is an effective and good choice for facilitation of adsorption process via. Compromise of simple and facile diffusion.

Ultrasonic assisted dispersive solid-phase microextraction of Eriochrome Cyanine R from water sample on ultrasonically synthesized lead (II) dioxide nanoparticles loaded on activated carbon: Experimental design methodology.

The present research focus on designing an appropriate dispersive solid-phase microextraction (UA-DSPME) for preconcentration and determination of Eriochrome Cyanine R (ECR) in aqueous solutions with aid of sonication using lead (II) dioxide nanoparticles loaded on activated carbon (PbO-NPs-AC). This material was fully identified with XRD and SEM. Influence of pH, amounts of sorbent, type and volume of eluent, and sonication time on response properties were investigated and optimized by central composite design (CCD) combined with surface response methodology using STATISTICA. Among different solvents, dimethyl sulfoxide (DMSO) was selected as an efficient eluent, which its combination by present nanoparticles and application of ultrasound waves led to enhancement in mass transfer. The predicted maximum extraction (100%) under the optimum conditions of the process variables viz. pH 4.5, eluent 200µL, adsorbent dosage 2.5mg and 5min sonication was close to the experimental value (99.50%). at optimum conditions some experimental features like wide 5-2000ngmL-1 ECR, low detection limit (0.43ngmL-1, S/N=3:1) and good repeatability and reproducibility (relative standard deviation, <5.5%, n=12) indicate versatility in successful applicability of present method for real sample analysis. Investigation of accuracy by spiking known concentration of ECR over 200-600ngmL-1 gave mean recoveries from 94.850% to 101.42% under optimal conditions. The procedure was also applied for the pre-concentration and subsequent determination of ECR in tap and waste waters.

Trace determination of safranin O dye using ultrasound assisted dispersive solid-phase micro extraction: Artificial neural network-genetic algorithm and response surface methodology.

In this study, ultrasound assisted dispersive solid-phase micro extraction combined with spectrophotometry (USA-DSPME-UV) method based on activated carbon modified with Fe2O3 nanoparticles (Fe2O3-NPs-AC) was developed for pre-concentration and determination of safranin O (SO). It is known that the efficiency of USA-DSPME-UV method may be affected by pH, amount of adsorbent, ultrasound time and eluent volume and the extent and magnitude of their contribution on response (in term of main and interaction part) was studied by using central composite design (CCD) and artificial neural network-genetic algorithms (ANN-GA). Accordingly by adjustment of experimental conditions suggested by ANN-GA at pH 6.5, 1.1mg of adsorbent, 10min ultrasound and 150µL of eluent volume led to achievement of best operation performance like low LOD (6.3ngmL(-1)) and LOQ (17.5ngmL(-1)) in the range of 25-3500ngmL(-1). In following stage, the SO content in real water and wastewater samples with recoveries between 93.27-99.41% with RSD lower than 3% was successfully determined.

Simultaneous ultrasound-assisted ternary adsorption of dyes onto copper-doped zinc sulfide nanoparticles loaded on activated carbon: optimization by response surface methodology.

The simultaneous and competitive ultrasound-assisted removal of Auramine-O (AO), Erythrosine (Er) and Methylene Blue (MB) from aqueous solutions were rapidly performed onto copper-doped zinc sulfide nanoparticles loaded on activated carbon (ZnS:Cu-NP-AC). ZnS:Cu nanoparticles were studied by FESEM, XRD and TEM. First, the effect of pH was optimized in a one-at-a-time procedure. Then the dependency of dyes removal percentage in their ternary solution on the level and magnitude of variables such as sonication time, initial dyes concentrations and adsorbent dosage was fully investigated and optimized by central composite design (CCD) under response surface methodology (RSM) as well as by regarding desirability function (DF) as a good and general criterion. The good agreement found between experimental and predicted values supports and confirms the suitability of the present model to predict adsorption state. The applied ultrasound strongly enhanced mass transfer process and subsequently performance. Hence, a small amount of the adsorbent (0.04 g) was capable to remove high percentage of dyes, i.e. 100%, 99.6% and 100% for MB, AO and Er, respectively, in very short time (2.5 min). The experimental equilibrium data fitting to Langmuir, Freundlich, Temkin and Dubinin-Radushkevich models showed that the Langmuir model applies well for the evaluation and description of the actual behavior of adsorption. The small amount of proposed adsorbent (0.015 g) was applicable for successful removal of dyes (RE>99.0%) in short time (2.5 min) with high adsorption capacity in single component system (123.5 mg g(-1) for MB, 123 mg g(-1) for AO and 84.5 mg g(-1) for Er). Kinetics evaluation of experiments at various time intervals reveals that adsorption processes can be well predicated and fitted by pseudo-second-order and Elovich models.