Nano chromium embedded in f-CNT supported CoBi-LDH nanocomposites for selective adsorption of Pb2+and hazardous organic dyes.

Transition metal-doped carbon-coated layered double hydroxides for the removal of lead (II) and hazardous organic dyes have attracted increasing attention for wastewater treatment in recent years. In this work, nanostructured CoBi-LDH/Cr@CNT composites were successfully synthesized by hydrothermal route. The CoBi-LDH/Cr@CNT was characterized by instrumental techniques such as XRD, FTIR, TEM, SEM, XPS and TGA/DTA. Adsorption of Pb2+ and organic dyes, i.e.,Rose Bengal (RB) and Congo red (CR) by CoBi-LDH/Cr@CNT was performed by batch experiment.The effect of several parameters including contact time, adsorbent dose, pH, temperature, and concentration was also investigated. Under optimum conditions, the adsorption capacity of CoBi-LDH/Cr@CNT for RB, CR and Pb2+ pollutants were (278.4 mg g-1), (164.6 mg g-1) and (503.2 mg g-1) and the removal efficiency achieved is 98.2%, 95.0% and 100% respectively. The selectivity of CoBi-LDH/Cr@CNT nanocomposite towards Pb2+ has been studied using ICP-AES.The isothermal results were analyzed using Freundlich and Langmuir models. Adsorption isotherm for Pb2+(R2 = 0.975), RB (R2 = 0.997) and CR (R2 = 0.992) agrees with the Langmuir model indicating monolayer adsorption. The sorption kinetics data well fitted pseudo-first-order model for Pb2+ (R2 = 0.975), RB (R2 = 0.996), and CR (R2 = 0.995).The results demonstrated that the synthesized CoBi-LDH/Cr@CNT nanocomposite can be used as an effective sorbent for the removal of pollutants from wastewater.

Selective adsorption and ultrafast fluorescent detection of Cr(VI) in wastewater using neodymium doped polyaniline supported layered double hydroxide nanocomposite.

Neodymium-doped polyaniline supported Zn-Al layered double hydroxide (PANI@Nd-LDH) nanocomposite has been prepared via an ex-situ oxidative polymerization process. The as-prepared nanocomposite shows selective fluorescence detection and adsorption of hexavalent chromium Cr(VI) within a short period. The fluorescence intensity of PANI@Nd-LDH decreases linearly with Cr(VI) concentrations ranging from 200 ppb to 1000 ppb with a limit of detection (LOD) of 1.5 nM and a limit of quantification (LOQ) of 96 nM. The sensing mechanism can be ascribed by the inner filter effect of Cr(VI), the intercalation of Cr(VI) within the intergallery region of LDH, and the synergistic affinity of metal ions along with the polymer chain for Cr(VI). The adsorption performance of PANI@Nd-LDH nanocomposite is evaluated for Cr(VI) from wastewaters, which displayed high removal capacity towards Cr(VI) (219 mg/g) as compared on bare Nd-LDH (123 mg/g) and LDH (88 mg/g) respectively. The adsorption of Cr(VI) on PANI@Nd-LDH depends on the pH of the aqueous solution. The adsorption isotherm and kinetics are supported by the Langmuir model and pseudo-second-order model, respectively. Owing to the highly sensitive detection and adsorption of Cr(VI) from aqueous water samples demonstrated the potential application of PANI@Nd-LDH as an excellent environmental probe can be exploited.

Staging Laparoscopy in Carcinoma of Stomach: A Comparison with CECT Staging.

Background. aim of this study was to compare the role of diagnostic laparoscopy and contrast enhanced computed tomography (CECT) of abdomen in the staging of stomach carcinoma. Methods. This was a prospective study conducted in a tertiary care hospital over a period of two years and included 50 patients of endoscopy and biopsy proven stomach carcinoma that were found to be operable on CECT. Diagnostic laparoscopy was performed in all patients before proceeding to a formal laparotomy. Results. Metastasis was detected at diagnostic laparoscopy in 14 (28%) patients. CECT correctly identified the T stage in 22 (61%) patients. Overall accuracy of CECT for T staging was 74% with a a sensitivity of 65% and a specificity of 79%. Laparoscopy correctly identified the T stage in 26 (72%) patients. Overall accuracy of laparoscopy for T staging was 81% with a sensitivity of 76% and specificity of 86%. the most common N stage on CECT was N0 (50%). CECT correctly identified the N stage in 26 (72%) patients. Overall accuracy of CECT for N staging was 86% with a sensitivity of 50% and a specificity of 90%. the most common N stage on laparoscopy was N0 and N2 (42% each). Laparoscopy correctly identified the N stage in 27 (75%) patients. Overall accuracy of Laparoscopy for N staging was 88% with a sensitivity of 53% and specificity of 91%. Conclusion. Laparoscopy is a valuable technique in staging of stomach carcinoma and has an important role in the detection of intra-abdominal metastasis missed by CECT.