Adsorption characteristics of arsenic and phosphate onto iron impregnated biochar derived from anaerobic granular sludge

Biological wastewater treatment produces biowaste (sludge), which contains a high portion of organic matter. The organic matter comes from microorganisms, and the biowaste can be converted into biochar, a carbon-rich, fine-grained, and porous substance. Granular sludge from upflow anaerobic sludge blanket contains more organic matter (80 wt% of dry matter) and carbon content (>50% of organic matter). In this study, iron impregnated biochar was prepared to remove arsenic (As) and phosphate, oxyanionic pollutants, from the aqueous phase. The iron impregnation of biochar was executed in a one-step by pyrolyzing the biowaste in the presence of Fe instead of conventional two-step, i.e., biochar production after then modification. The granular sludge biochar and activated sludge biochar did not adsorb at all As and phosphate. The adsorption capacity of granular sludge biochar was enhanced via iron impregnation, and the iron-impregnated granular sludge biochar removed 10.37 mg PO ₄ ^3- /g, 11.5 mg As(V)/g, and 6.1 mg As(III)/g, respectively. Therefore, the one-step process enhanced the adsorption capacity and reduced processing time for the adsorbent synthesis.     

Radon exposure assessment for underground workers: a case of Seoul Subway Police officers in Korea

The objective of this study is the systematic and individual assessment of the annual effective dose due to inhaled radon for the Seoul Subway Police officers, Korea. The annual average radon concentrations were found to be in the range of 18.9-114 Bq·m(-3) in their workplaces. The total annual effective doses which may likely to be received on duty were assessed to be in the range of 0.41-1.64 mSv·y(-1). These were well below the recommended action level 10 mSv·y(-1) by ICRP. However, the effective doses were higher than subway station staff in Seoul, Korea.     

Medically used radionuclides (131I, 99mTc) in the urban sewage system: the case of the Daejeon metropolitan city, Korea

In order to assess the behaviour of radioactivity (specifically (131)I concentrations in wastewater and sludge at sewage treatment plant) discharged into municipal sewage by therapy patients receiving treatment, the use of radiopharmaceuticals in four hospitals was quantitatively evaluated and the patients were classified by their residence. (131)I concentrations were estimated using a simple assumption model for radioiodine treatments of 94 patients, and measured by HPGe in inflow points, respectively. A good agreement was found between (131)I concentrations estimated with the model and those measured in the inflow points at the sewage treatment plant.     

Super TEX-SIM: Interactive textile design and simulation

This paper presents an interactive tool for designing and simulating textile images. It comprises a yarn editor, a textile editor and a texture mapper. These subsystems share a colour editor that can modify the colours of yarn and textile images interactively. We describe how yarn and textile images are generated, and how they are mapped to a target picture read from an image scanner. The user interface in the tool has many useful functions so that users can design textile images without knowledge of computer graphics and programming languages. Several examples of texture mapping are included.     

Ultrafast Charging of a 4.8 V Manganese-Rich Cathode-Based Lithium Metal Cell by Constructing Robust Solid Electrolyte Interphases

Fast charging of Li-metal battery (LMB) is a challenging issue owing to the interfacial instability of Li-metal anode in liquid electrolyte and Li-dendrites growth, resulting in fire hazard. Those issues motivated to pioneer a stabilization strategy of liquid electrolyte-derived solid electrolyte interphase (SEI) layer that enables dendrites-free Li-metal anode under extremely high current density, which solid-state battery cannot. Here, the novel electrolyte formulation is reported including trace-level pentafluoropropionic anhydride (PFPA) combined with fluoroethylene carbonate (FEC) additives, and the SEI stabilization in Li//Mn-rich LMB, achieving unprecedented ultrafast charging under simultaneous extreme conditions of 20 C (charged in 3 min), 4.8 V and 45 °C, delivering 118 mAh g⁻¹ for long reversible 400 cycles, and unprecedented high stability of Li//Li cell under extremely high current 10 mA cm⁻² (Li stripping/plating in 6 min) for a prolonged time of 200 h. The SEI analysis results reveal that the PFPA, which has a symmetric 10 F-containing molecular structure, is a strong F source for promptly producing thin, uniform, and robust F- and organics-enriched SEI layers at both Li-metal anode and Mn-rich cathode, preventing Li-dendrites. This study provides a potential concept for ultrafast charging, long-cycled, and safer high-energy LMBs and LIBs.