Biochar Production and Demineralization Characteristics of Food Waste for Fuel Conversion.

The pyrolysis of food waste has high economic potential and produces several value-added products, such as gas, bio-oil, and biochar. In South Korea, biochar production from food waste is prohibited, because dioxins are generated during combustion caused by the chloride ions arising from the high salt content. This study is the first to examine the water quality and the applicability of food waste-based biochar as solid refuse fuel (SRF) based on a demineralization process. The calorific value increased after demineralization due to the removal of ionic substances and the high carbon content. The chloride ion removal rate after demineralization increased with the increasing pyrolysis temperature. A proximate analysis of biochar indicated that the volatile matter decreased, while ash and fixed carbon increased, with increasing pyrolysis temperature. At 300 °C pyrolysis temperature, all domestic bio-SRF standards were met. The organic matter concentration in water decreased with increasing carbonization temperature, and the concentrations of soluble harmful substances, such as volatile organic compounds (VOCs), were within the standards or non-detectable. These results suggest that biochar can be efficiently generated from food waste while meeting the emission standards for chloride ions, dissolved VOCs, ash, and carbon.

Effects of demineralization on food waste biochar for co-firing: Behaviors of alkali and alkaline earth metals and chlorine.

A significant amount of chlorine, and alkali and alkaline earth metal (AAEM) in food waste has been a major limitation to the utilization of food waste as fuel. The present study aims to investigate the behavior of chlorine and AAEM in food waste biochar during pyrolysis, demineralization, and combustion. Food waste compost (FWC) and food waste feedstock (FWF) were selected as raw materials. Three different pyrolysis temperatures from 300 to 500 °C and two demineralization processes, water and CO2-saturated water, were employed. As the pyrolysis temperature increased, crystallized salt was removed through demineralization, which further increased the heating value. Effective removal of chlorine was demonstrated in both demineralization methods. During demineralization, re-adsorption of Ca on food waste biochar occurred, which was alleviated by CO2-water demineralization. The total amounts of volatilized Cl and AAEM after CO2-water demineralization were reduced by 74.79-99.38% for FWF and 98.34-99.9% for FWC compared to raw biochar. Furthermore, slagging and fouling potentials for all food waste biochar samples were estimated using various indices. The proposed behavior of Cl and AAEM in food waste biochar during various fabrication conditions provides insight into how food waste biochar can be applied in thermos-electric power plant for co-firing with coal.

Pyrolytic valorization of water treatment residuals containing powdered activated carbon as multifunctional adsorbents.

This study investigated the possibility of applying pyrolysis as an alternative method to recycle powdered activated carbon-containing water treatment residuals (PAC-WTRs) discharged from the Cheongju water treatment plant as a multifunctional adsorbent. WTRs pyrolyzed for 1 h at 200-700 °C were compared with raw material. The carbon content of the PAC-WTR reaches 19.27%, with about 25% Al and 17% Si. Changes in PAC through pyrolysis imparted new adsorbent properties to WTR. As the pyrolysis temperature increased, the purity of PAC increased, and pores were regenerated to recover the Brunauer-Emmett-Teller (BET) from 6.5 m2 g-1 to 131.8 m2 g-1. In addition, the basicity increased as the carboxylic and phenolic groups on the carbon surface were decomposed, which increased the cation (methylene blue) adsorption capacity and reduced heavy metal leaching. As the coagulant regenerated with increasing pyrolysis temperature, the amount of aluminum leached and phosphate removal efficiency were increased. In the case of simultaneous removal of cations (MB+) and anions (PO43-), the removal efficiency was higher than that for single adsorption without competition through multi-layer adsorption by Al complex and PAC complex. Therefore, the pyrolyzed PAC-WTR is capable of adsorbing and removing anions and cations simultaneously without the peril of substance leaching. The regenerated WTRs containing PAC is expected to be utilized as a multi-functional remediation material for wastewater containing various pollutants.

T Cell Immunoglobulin Mucin Domain (TIM)-3 Promoter Activity in a Human Mast Cell Line.

T cell immunoglobulin mucin domain (TIM)-3 is an immunomodulatory molecule and upregulated in T cells by several cytokines. TIM-3 also influences mast cell function but its transcriptional regulation in mast cells has not been clarified. Therefore, we examined the transcript level and the promoter activity of TIM-3 in mast cells. The TIM-3 transcript level was assessed by real-time RT-PCR and promoter activity by luciferase reporter assay. TIM-3 mRNA levels were increased in HMC-1, a human mast cell line by TGF-ß1 stimulation but not by stimulation with interferon (IFN)-α, IFN-λ, TNF-α, or IL-10. TIM-3 promoter -349~+144 bp region relative to the transcription start site was crucial for the basal and TGF-ß1-induced TIM-3 promoter activities in HMC-1 cells. TIM-3 promoter activity was increased by overexpression of Smad2 and Smad4, downstream molecules of TGF-ß1 signaling. Our results localize TIM-3 promoter activity to the region spanning -349 to +144 bp in resting and TGF-ß1 stimulated mast cells.

Identification of CCL1 as a Gene Differentially Expressed in CD4 T Cells Expressing TIM-3.

BACKGROUND: T cell immunoglobulin mucin containing molecule (TIM)-3 is expressed in differentiated Th1 cells and is involved in the suppression of the cytokine production by these cells. However, the regulation of the expression of other T cell genes by TIM-3 is unclear. Herein, we attempted to identify differentially expressed genes in cells abundantly expressing TIM-3 compared to cells with low expression of TIM-3. METHODS: TIM-3 overexpressing cell clones were established by transfection of Jurkat T cells with TIM-3 expression vector. For screening of differentially expressed genes, gene fishing technology based on reverse transcription-polymerase chain reaction (RT-PCR) using an annealing control primer system was used. The selected candidate genes were validated by semi quantitative and real-time RT-PCR. RESULTS: The transcription of TIMP-1, IFITM1, PAR3 and CCL1 was different between TIM-3 overexpressing cells and control cells. However, only CCL1 transcription was significantly different in cells transiently transfected with TIM3 expression vector compared with control cells. CCL1 transcription was increased in primary human CD4(+) T cells abundantly expressing TIM-3 but not in cells with low expression of TIM-3. CONCLUSION: CCL1 was identified as a differentially transcribed gene in TIM-3-expressing CD4(+) T cells.

Activation of mitogen activated protein kinase-Erk kinase (MEK) increases T cell immunoglobulin mucin domain-3 (TIM-3) transcription in human T lymphocytes and a human mast cell line.

The immune regulatory molecule T cell immunoglobulin mucin domain (TIM-3) is expressed in activated T cells and in mast cells treated with transforming growth factor (TGF)-ß, but underlying mechanisms for induction of TIM-3 transcription have not been well-explored. We studied the role of mitogen-activated protein kinase (MAPK) in TIM-3 transcription on the basis of the involvement of MAPK in T cell activation and TGF-ß signaling. Inhibitors of MAPK-Erk kinase (MEK) as well as p38 suppressed TIM-3 transcription in phorbol myristic acid (PMA)-stimulated T cells, but inhibitors of c-Jun NH2-terminal kinase (JNK) did not. MEK over-expression enhanced TIM-3 transcription in PMA-stimulated T cells. Furthermore, -1.5kb TIM-3 promoter was activated by PMA stimulation and repressed by MEK inhibitors in Jurkat T cells. Similarly, MEK activation enhanced TIM-3 transcription in TGF-ß-stimulated HMC-1 human mast cells, although MEK seemed not directly activated by TGF-ß. Concordantly, -1.5kb TIM-3 promoter activity was reduced by MEK inhibitors, but was not responsive to TGF-ß stimulation in HMC-1 cells. These results suggest the regulatory role of MEK in TIM-3 transcription by human CD4+ T cells and mast cells.

Improved imaging of the cervico-thoracic junction in computed tomography.

PURPOSE: To reduce beam hardening artifacts caused by the shoulder joint, we explored new and unique methods to improve the quality of images, such as varying the injection site and changing the position of patients (swimmers position). MATERIALS AND METHODS: Fifth-four patients underwent neck CT examinations performed in routine and swimmers position and with a 64-slice MDCT scanner in spiral scanning. To examine the difference due to the injection sites of contrast material, subjects were divided into right- and left-side groups. For the evaluation of images, we carried out a subjective and objective assessment based on radiologists' ratings and noise measurement. RESULTS: Images of the lower neck in the swimmers position exhibited less hardening and streak artifacts. The subjective and objective evaluations showed that the swimmers position received higher rating by radiologists and had lower noise level than that of routine position. The swimmers position was the most effective for the diagnosis of the cervico-thoracic junction area. As for the injection site, we obtained better images by an injection of contrast material in the right arm than in the left. CONCLUSION: CT examination of the lower neck in the swimmers position may improve the quality of image and the effectiveness of diagnosis. The injection of a contrast material to the right side rather than the left side reduced foreign body artifacts.