Adsorption, Equilibrium Isotherm, and Thermodynamic Studies towards the Removal of Reactive Orange 16 Dye Using Cu(I)-Polyaninile Composite

To overcome some of the limitations of activated carbon like efficiency, cost-effectiveness, and reusability, the present work deals with Cu(I)-based polyaniline (PANI) composite for the removal of reactive orange 16 (RO16) dye. Following the synthesis and characterization of formed Cu(I)-PANI composite, the batch experiments performed for the removal of RO16 dye indicated that the composite has the capacity to reduce the coloring from RO16. The experiments were conducted for the study of effects against changes in pH, time, and dose at room temperature, where we observed for a pH impact on the dye adsorption capacity in the range of 2–12. Among all, the optimal RO16 removal was found to be 94.77% at a pH of 4 and in addition, the adsorption kinetics confirmed to be pseudo-second-order with more suitability towards the Langmuir isotherm, where it is presumed to be the formation of a monolayer of dye molecule at the homogeneous absorbent surface. The calculated maximum capacity, qm, determined from the Langmuir model was 392.156 mg/g. Further application of isotherms to attain thermodynamic parameters, a slight positive value of S° for RO16 adsorption was observed, meaning that there is an increased randomness in the irregular pattern at the specific Cu(I)-PANI interface for an adsorption process. This mechanism plays an essential role in maintaining the effects of water pollution; and, based on the analysis therefore, it is prominent that the Cu(I)-PANI composite can be employed as a promising and economical adsorbent for the treatment of RO16 and other dye molecules from the sewage in wastewater.

Selective Adsorption and Separation of Proteins by Ligand-Modified Nanofiber Fabric

Electrospun polyvinyl alcohol (PVA) nanofiber fabric was modified by Cibacron Blue F3GA (CB) to enhance the affinity of the fabric. Batch experiments were performed to study the nanofiber fabric’s bovine hemoglobin (BHb) adsorption capacity at different protein concentrations before and after modification. The maximum BHb adsorption capacity of the modified nanofiber fabric was 686 mg/g, which was much larger than the 58 mg/g of the original fabric. After that, the effect of feed concentration and permeation rate on the dynamic adsorption behaviors for BHb of the nanofiber fabric was investigated. The pH impact on BHb and bovine serum albumin (BSA) adsorption was examined by static adsorption experiments of single protein solutions. The selective separation experiments of the BHb–BSA binary solution were carried out at the optimal pH value, and a high selectivity factor of 5.45 for BHb was achieved. Finally, the reusability of the nanofiber fabric was examined using three adsorption–elution cycle tests. This research demonstrated the potential of the CB-modified PVA nanofiber fabric in protein adsorption and selective separation.

Neglect of Temperature and pH Impact Leads to Underestimation of Seasonal Ecological Risk of Ammonia in Chinese Surface Freshwaters

Ammonia nitrogen (AN) is evaluated with fixed water quality standards (WQSs) in aquatic environment management in China. Since the toxicity of AN can be influenced by water parameters, the current evaluation is not rigorous and may result in problematic conclusions. The present study collected the ecotoxicity and exposure data of AN in Chinese surface freshwaters in 2017. The species sensitivity distribution of AN was established, and the ecological risk posed by AN in Chinese surface waters was assessed with Chinese AN water quality criteria. The results showed that mollusk species are the most sensitive taxa to AN. Ecological risk assessments on AN suggested that, in summer and autumn, when the water temperature and pH are high, the risk of AN may occur at some sites with good water quality (Class II or III). This poses a threat to aquatic organisms at these sites, especially highly sensitive freshwater shellfish. It suggested that neglect of water parameters impact may lead to underestimation of ecological risk of AN in Chinese basins.

Adsorption of Pb2+ from aqueous solution using spinel ferrite prepared from steel pickling sludge

In this paper, spinel ferrite with high crystallinity and high saturation magnetization was successfully prepared from steel pickling sludge by adding iron source and precipitator in the hydrothermal condition. The obtained spinel ferrite was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), vibrating sample magnetometer (VSM), and Zeta potential methods and investigated as an adsorbent for removal of Pb2+ from aqueous solution. Batch experiments were performed by varying the pH values, contact time, temperature and initial metal concentration. The result of pH impact showed that the adsorption of Pb2+ was a pH dependent process, and the pH 5.8 ± 0.2 was found to be the optimum condition. The achieved experimental data were analyzed with various kinetic and isotherm models. The kinetic studies revealed that Pb2+ adsorption onto spinel ferrite followed a pseudo-second order model, and the Langmuir isotherm model provided the perfect fit to the equilibrium experimental data. At different temperatures, the maximum Pb2+ adsorption capacities calculated from the Langmuir equation were in the range of 126.5–175.4 mg/g, which can be in competition with other adsorbents. The thermodynamic results showed that the spinel ferrite could spontaneously and endothermically adsorb Pb2+ from aqueous solution. The regeneration studies showed that spinel ferrite could be used five times (removal efficiency (%) >90%) by desorption with HNO3 reagent.

Abstract 13099: Study of Right Ventricular to Pulmonary Circulation Uncoupling at Peak Exercise in Heart Failure by gas Exchange Analysis Combined to Echocardiography

Background: Right ventricular (RV) dysfunction and pulmonary hypertension (PH) impact on clinical status and have a prognostic value in heart (HF) patients. There is interest in assessment the RV to pulmonary circulation (PC) uncoupling during exercise even though much needs to be defined on the functional phenotypes. Aim: to define how the degrees of RV-PC uncoupling may engender specific functional phenotypes. Methods: 94 HFrEF patients (mean age 66±11 y, male 70%, ischemic etiology 71%, mean LVEF 34±9%) underwent a maximal CPET (incremental ramp protocol) combined with exercise-echo. Results: Population was divided into 4 groups using the 4 quadrant approach (Figure) based on TAPSE vs systolic PAP (PASP) relationship as a length vs developed force of the RV during exercise (cutoff based on median values of 20 mm and 57 mmHg). At peak exercise patients with more favorable TAPSE vs PASP relationship (group A) showed the better functional CPET response (higher peak VO2; lower VE/VCO2 slope and prevalence of exercise oscillatory ventilation (EOV), p= 0.000, 0.005 and 0.000). Group B and C showed similar peak VO2 and the occurrence of dynamic PH (group C) was related to dynamic mitral regurgitation (MR) and high rate of EOV (B vs C p=0.001 and 0.000). Interestingly, for similar exercise tolerance and LV function parameters, group D patients had more severely impaired ventilatory efficiency associated with very high prevalence of rest severe (MR) and EOV (p=0.005, 0.002). Conclusions: This proposed non-invasive RV functional evaluation approach at peak exercise seems appealing for stageing HF syndrome severity based on the degree of the right heart dysfunction. It appears also useful to unmask different ventilatory phenotypes irrespective of a similar impairment in functional capacity and peak VO2.