N-doped porous bowl-like carbon with superhigh external surface area for ultrafast degradation of bisphenol A: Key role of site exposure degree.

High-temperature nitrogen (N) doping boosts the activity of biochars for peroxymonosulfate (PMS) activation, but the N heat loss causes the unsatisfactory catalytic efficiency. Improving the surface area for obtaining the high exposure of N sites is a promising solution. Herein, a soft template-KHCO3 etching strategy is used to synthesize the N-doped porous bowl-like carbon (NPBC) with ultrahigh external surface area (1610.8 m2 g-1). The bowl-like structure eliminates inert bulk interior and allows unobstructed mass transfer of reactants onto both outer and inner surfaces, while the large pore channels by KHCO3 etching further improves the exposure degree of limited N sites. Although NPBC has only 0.43% N content, 93.1% of bisphenol A (BPA) is removed within 1 min through the electron-transfer pathway by fully utilizing the N active centers, and the kinetic rate constant (k) reaches 5.29 min-1, exceeding reported values by 2-270 times. Moreover, the NPBC/PMS system possesses excellent applicability for various organics and conditions, effectively mineralizes BPA and reduces effluent biotoxicity. A quantitative index W representing N exposure degree is first proposed and shows high linearity with the k values of BPA degradation (R2=0.992, 0 

Rapid removal of copper with magnetic poly-acrylic weak acid resin: quantitative role of bead radius on ion exchange.

A novel magnetic weak acid resin NDMC was self-synthesized for the removal of Cu(2+) from aqueous solutions. NDMC showed superior properties on the removal of Cu(2+) compared to commercial resins C106 and IRC-748, which was deeply investigated by adsorption isotherms and kinetic tests. The equilibrium adsorption amount of Cu(2+) onto NDMC (267.2mg/g) was almost twice as large as that onto IRC-748 (120.0mg/g). The adsorption kinetics of Cu(2+) onto the three resins fitted well with the pseudo-second-order equation. The initial adsorption rate h of NDMC was about 4 times that of C106 and nearly 8 times that of IRC-748 at the initial concentration of 500mg/L. External surface area was determined to be the key factor in rate-controlling by further analyzing the adsorption thermodynamics, kinetics parameters and physicochemical properties of the resins. NDMC resin with the smallest bead radius possessed the largest external surface and therefore exhibited the fastest kinetics. The adsorption amount of Cu(2+) onto NDMC was not influenced as the concentration of Na(+) increased from 1.0 to 10.0mM/L. Dilute HCl solution could effectively desorb Cu(2+). NDMC demonstrated high stability during 10 adsorption/desorption cycles, showing great potential in the rapid removal of Cu(2+) from wastewater.

SMP production by activated sludge in the presence of a metabolic uncoupler, 3,3',4',5-tetrachlorosalicylanilide (TCS).

3,3',4',5-Tetrachlorosalicylanilide (TCS) is an effective metabolic uncoupler utilized for microbial yield reduction. However, its potential impact, in particular on the soluble microbial products (SMP) formation, is unknown yet. Herein we study the effect of TCS on SMP production and analyze the related mechanism. The addition of TCS in activated sludge system led to an increased production of SMP, especially proteins. The SMP were produced in proportion to the substrate utilization at a low TCS concentration, while more non-substrate-associated SMP were released at a high TCS concentration. TCS simulated the production of extracellular polymeric substances (EPS) and enhanced cell lysis, which both contributed to SMP production. FTIR and EEM analyses show that the SMP, EPS, and cell lysis products have similar functional groups and fluorescence properties, indicating a similar origin of these substances. In addition, a dose of TCS increased the release of high molecular weight compounds due to cell lysis. This study might benefit for a better understanding of the response of activated sludge to metabolic uncouplers like TCS.

Assessment of the manganese content of the drinking water source in Yancheng, China.

Excessive intake of manganese can damage the nervous system of the human body. In August 2009, the manganese content of the drinking water source in Yancheng exceeded the national standard of drinking water source, which influenced the daily life of the local residents. The aim of this study was to investigate the factors leading to the manganese content of river water in Yancheng exceeding the national standard. To the data, the manganese content of surface water in Yancheng already met the national standard of drinking water source in September 2009, but the manganese content of river sediment was relatively high, especially in Mangshe River and Tongyu River. It was worthwhile to note that the soluble manganese content of the sediment in Mangshe River was even as high as 270 mg kg(-1), which suggested that the release of manganese from the sediment was the major cause of the pollution. The manganese content of the soil near the rivers was also determined, and the results indicated that the wastewater and waste slag discharged by the stainless steel factories nearby were the main pollution sources of manganese. Furthermore, the environmental factors affecting the release of manganese from the sediment were also investigated.