25 research outputs found

    Outcomes from elective colorectal cancer surgery during the SARS-CoV-2 pandemic

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    This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic

    Investigation of sorption characteristics of anaerobically digested dewatered municipal sewage sludge

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    Physical, chemical, morphological properties and sorption characteristics of anaerobically digested dewatered municipal sewage sludge have been investigated including the surface area, pore size distribution, chemical composition, surface chemistry structure, surface physical morphology, mineralogy, cation exchange capacity, heavy metal content, total solid, total volatile solid, total Kjeldahl-N, total phosphorus content of the sewage sludge. The sorption potential of sewage sludge for the removal of 4-CP and 2,4-DCP from aqueous solutions was examined by investigating their adsorption isotherms and kinetics in a lab-scale batch study. Findings of this study clearly showed that sewage sludge provides chlorophenol removal in the landfill body as disposed with solid wastes

    Modeling and optimization of syngas production from biomass gasification

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    The detrimental environmental impacts of fossil fuels are increasing due to the growing global energy consumption. Thus, energy recovery from waste will inevitably become the dominant option in the future with population growth and the reduction in fossil resources. In this study; the synthesis gas composition obtained by gasification of biomass attained from a mixture of carbon black obtained from waste tires and sewage sludge originating from the yarn industry was modeled by the response surface method and optimized using Box-Behnken design. The R-2 values obtained for H-2, CO, CH4, and the heating value that make up the synthesis gas composition are 92.86%, 95.40%, 96.15%, and 96.80%, respectively. These are the indicators that the models were statistically significant. Optimum conditions obtained from the model were as follows; reaction time 31.14 min, gas flow rate 0.05 L/minute, and biomass amount 19.66 g. As a result of the validation experiments conducted under optimum conditions, the percentages of H-2, CH4, CO were found as 12.75%, 8.07%, and 7.87%, respectively, and the heating value was 1420.3 kcal/m(3). In conclusion, the gasification process is an appropriate treatment for obtaining high-quality syngas from waste materials with high carbon and low moisture content and the Box-Behnken design is applicable for the optimization of the gasification process

    Equilibrium and kinetic studies on the removal of heavy metal ions with natural low-cost adsorbents

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    Adsorption isotherms and kinetics of the removal of heavy metal ions (Ni, Pb, Zn) from aqueous solutions by natural adsorbents (zeolite, bentonite, clay) were investigated in a lab-scale batch study. The effect of various parameters such as adsorbent dosage, initial concentration of heavy metal ions, temperature, and agitation time were studied to optimise the conditions. Under those optimized conditions (180 rpm agitation rate, 120 min agitation time, pH 4.0, 298 K, 100 mg/dm3 initial adsorbate concentration), the removal percentages of heavy metal ions for natural adsorbents have been determined. The adsorption mechanisms and characteristic parameters of the process were analyzed by two and three parameter isotherm models (Langmuir, Freundlich, Temkin, Redlich-Peterson, Toth and Sips), and kinetic models (Lagergren's pseudo-first order, Ho and McKay's pseudo-second order). Adsorption thermodynamics of heavy metal ions (changes of standard enthalpy, entropy and free energy) on zeolite, bentonite and clay were also studied at 298,318 and 338 K
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