Reduction of nitrate using biochar synthesized by Co-Pyrolyzing sawdust and iron oxide.

Nitrate is the most common contaminant in groundwater in Korea, as well as across the world. Reduction of nitrate to ammonia is one of the options available to remediate groundwater. In this study, nitrate in groundwater was removed using a zero-valent iron (ZVI) containing biochar synthesized by co-pyrolyzing iron oxide and sawdust biomass. Among the various biogases generated during the pyrolysis of biomass, CO and H2 act as reducing agents to transform iron oxides to ZVI. Approximately 71% of nitrate was reduced to ammonium by ZVI-biochar at initial pH 2.0, and the reduction decreased sharply by the increase in pH. The mass of nitrate-N decreased is exactly same with the mass of ammonia-N formed. However, ammonium remained in the aqueous phase after reduction by ZVI-biochar, and the total nitrogen was not lowered. Acid-washed zeolite adsorbed most ammonium reduced by the ZVI-biochar and maintained the pH to acidic condition to facilitate the reduction of nitrate. The results of this study imply that nitrate-contaminated groundwater can be properly treated within the guidelines of water quality by synthesized ZVI-containing biochar.

Layered Double Hydroxide Quantum Dots for Use in a Bifunctional Separator of Lithium-Sulfur Batteries.

Functional separators, which are chemically modified and coated with nanostructured materials, are considered an effective and economical approach to suppressing the shuttle effect of lithium polysulfide (LiPS) and promoting the conversion kinetics of sulfur cathodes. Herein, we report cobalt-aluminum-layered double hydroxide quantum dots (LDH-QDs) deposited with nitrogen-doped graphene (NG) as a bifunctional separator for lithium-sulfur batteries (LSBs). The mesoporous LDH-QDs/NG hybrids possess abundant active sites of Co2+ and hydroxide groups, which result in capturing LiPSs through strong chemical interactions and accelerating the redox kinetics of the conversion reaction, as confirmed through X-ray photoelectron spectroscopy, adsorption tests, Li2S nucleation tests, and electrokinetic analyses of the LiPS conversion. The resulting LDH-QDs/NG hybrid-coated polypropylene (LDH-QDs/NG/PP) separator, with an average thickness of ∼17 µm, has a high ionic conductivity of 2.67 mS cm-1. Consequently, the LSB cells with the LDH-QDs/NG/PP separator can deliver a high discharge capacity of 1227.48 mAh g-1 at 0.1C along with a low capacity decay rate of 0.041% per cycle over 1200 cycles at 1.0C.

Continuous microalgae recovery using electrolysis: effect of different electrode pairs and timing of polarity exchange.

Microalgae have great potential as a feedstock for biofuel production. Continuous operation is an important benefit of the continuous electrolytic microalgae (CEM) harvest system, but it is necessary to optimize cultivability and recovery efficiency in order to improve overall performance. Two pairs of best-candidate electrodes for polarity exchange (PE) were examined to improve these two key factors: (i) aluminum and dimensionally stable anode (Al-DSA), and (ii) Al-platinum (Al-Pt). Al-DSA was better than Al-Pt because it led to less cell damage and was less expensive. Moreover, cell viability and recovery were improved by optimizing the timing of PE. A P1:P2 ratio of 1:1.5 at 5min and 1:1.2 at 10min yielded the best results, with greatly reduced electricity consumption and enhanced cell viability and recovery. The CEM harvest system appears to be a well-suited option for the harvest of microalgae for biofuel production.

Identification and characterization of triamcinolone acetonide, a microglial-activation inhibitor.

Recent studies show that necrotic neuronal cells (NNC) activate microglia, thereby leading to neuronal cell death. This suggests that chemicals that inhibit microglia activation may be used as neuroprotective drugs. In this context, we screened a chemical library for inhibitors of microglia activation. Using a screening system based on a nitrite assay, we isolated two chemicals that inhibit nitric oxide (NO) release from activated microglia: triamcinolone acetonide (TA) and amcinonide. The half-maximal inhibitory concentrations (IC50) of TA and amcinonide for NO release inhibition were 1.78 nM and 3.38 nM, respectively. These chemicals also inhibited NNC-induced expression of the proinflammatory genes iNOS, TNF-α, and IL-1ß in glial cells. A study based on a luciferase assay revealed that TA attenuated NNC-induced microglia activation by blocking the NF-κB signaling pathway. In addition, TA protected cortical neurons in coculture with microglia from LPS/IFN-γ-induced neuronal cell death. In conclusion, TA may inhibit microglia activation and may protect neuronal cells from death induced by microglial activation.

Continuous microalgae recovery using electrolysis with polarity exchange.

There is increasing interest in the use of microalgae as a renewable source for the production of fuels and chemicals, but improvements are needed in all steps of this process, including harvesting. A continuous microalgae harvest system was developed based on electrolysis, referred to here as a continuous electrolytic microalgae (CEM) harvest system. This innovative system combines cultivation and harvesting and enables continuous and efficient concentration of microalgae. The electrodes were subject to a polarity exchange (PE) in the middle of the operation to further improve the harvest efficiency. Use of PE, rather than conventional electro-coagulation-flotation (ECF), led to more efficient cell recovery and more uniform recovery over the entire harvest chamber. In addition, PE increased the cell growth rate and the circulated cells remained intact after harvesting.

Humic substance-enhanced ultrafiltration for removal of cobalt.

It is well known that the membrane separation process combined with surfactant micelle (micellar-enhanced ultrafiltration) or polyelectrolyte (polyelectrolyte-enhanced ultrafiltration) can remove heavy metal ions or radionuclides effectively. However, the complexing agent, surfactant or polyelectrolyte remained in effluent is a serious disadvantage of these methods. In this study, humic substances (HS) were used as complexing agents instead of synthetic chemicals. The HS are sorts of natural organic matters and their functional groups such as carboxyl and phenyl groups can bind with the cation and form complexes. The effects of HS concentration and pH on the removal of cobalt were investigated. At the HS concentration of 3g/L and pH of 6, over 95% of cobalt was removed by regenerated cellulose membrane with molecular weight cut-off (MWCO) of 3000. As the HS concentration increased, the removal of cobalt was also enhanced because of the increase in binding sites (functional groups). The removal of cobalt increased from 72.5% to 97.5% as pH increased from 4 to 8 at the HS concentration of 3g/L. It resulted from the more deprotonation of functional groups in humic acid at higher pH.

Removal characteristics of anionic metals by micellar-enhanced ultrafiltration.

Surfactant-based separation of Fe(CN)(6)(3-) and CrO(4)(2-) using regenerated cellulose membrane was studied in order to assess the potential of micellar-enhanced ultrafiltration for the remediation of wastewater or groundwater polluted with ferriccyanide and chromate. In the ferriccyanide/octadecylamine acetate (ODA) and chromate/ODA systems, removal of ferriccyanide increased from 73 to 92% and to 98%, and that of chromate from 64 to 97% and to >99.9% as the molar ratio of ODA to ferriccyanide and to chromate increased from 1 to 2 and to 3, respectively. In the ferriccyanide/chromate/ODA system, while the removal of ferriccyanide increased from 62 to 72% and to 93%, the removal of chromate from 20 to 38% and to 68% as the molar ratio of ferriccyanide:chromate:ODA increased from 1:1:1 to 1:1:2 and to 1:1:4, respectively. With the molar ratio of 1:1:6, the removal was >99.9 and 98% for chromate and ferriccyanide, respectively. Ferriccyanide ions were more easily bound to ODA micelles because the binding power of ferriccyanide was greater than that of chromate.

The Relation between Histopathologic Findings on Surgical Specimen and Outcomes in Patients with N2 Positive Stage IIIA Non-Small Cell Lung Cancer Receiving Preoperative Concurrent Radiochemotherapy and Surgery.

PURPOSE: To evaluate the prognostic implication of histopathologic findings on the surgical specimens of N2 positive stage IIIA non-small cell lung cancer (NSCLC) patients who were treated with preoperative concurrent radiochemotherapy (CRCT) and surgery. MATERIALS AND METHODS: From May 1997 to April 2000, 48 patients with N2 positive stage IIIA NSCLC were treated with preoperative CRCT and surgery. Retrospective analyses were performed on 33 patients who underwent surgical resection. The thoracic radiation therapy (TRT) dose was 45 Gy over 5 weeks with a 1.8 Gy daily fraction using 10 MV X-rays. Chemotherapy consisted of two cycles of intravenous cisplatin (100 mg/m2, on days 1 and 29) and oral etoposide (50 mg/m2/day, on days 1~14 and 29~42), concurrently delivered with TRT. Surgery was performed around 4 weeks of the completion of CRCT. The median follow up was 18 months. The histopathologic findings, including the proportions of viable tumor cells, fibrosis, and necrosis, as well as the tumor and nodal statuses on the surgical specimens following the preoperative CRCT, were analyzed. RESULTS: The 3-year overall survival, disease-free survival, and local control rates were 46.1%, 49.5%, and 85.5%, respectively. Post-surgical stages decreased in 18 patients (54.5%), including 3 pathologic complete responses, were unchanged in 13 (39.4%), and increased in two (6.1%). On univariate analyses, the low proportion of the viable tumor cells was the only factor favorably affecting the overall survival rate (p=0.0386), and the histologic type of squamous cell carcinoma was a favorable factor affecting disease free survival rate (p=0.0452). On multivariate analyses, however, no factor affected the overall survival, disease free survival, or local control rates. CONCLUSION: The histopathologic findings of the proportion of viable tumor cells, fibrosis, and necrosis on the surgical specimens following preoperative CRCT had few prognostic implications on uni-and multi-variate analyses. Furthermore, the primary tumor and nodal responses to preoperative CRCT did not influence the outcomes. Longer-term follow-up with a larger number of patients, however, is awaited.