The degradation of solutions of the antibiotic tetracycline (TC) has been studied by a novel electrochemical advanced oxidation process, consisting in electro-Fenton (EF) process using chalcopyrite as heterogeneous catalyst. In fact, chalcopyrite powder was the source of Fe 2+ and Cu 2+ ions instead of a soluble catalyst salt used in conventional EF. Experiments were performed in an undivided cell equipped with a Pt or boron-doped diamond (BDD) anode and a carbon felt cathode, where TC and its oxidation intermediate products were destroyed by hydroxyl radicals ( OH) formed both, in the bulk solution from electrochemically induced Fenton’s reaction (Fe 2+ and H 2 O 2 ) and Fenton’s-like reaction (Cu + and H 2 O 2 ), and at the anode surface from water oxidation. The effects of operating parameters such as applied current, chalcopyrite concentration and anode material were investigated. TC decay followed pseudo-first-order reaction kinetics. The absolute rate constant for TC oxidation by OH was found to be 3.2 × 10 9  M −1  s −1 , as determined by the competition kinetic method. EF process using chalcopyrite as heterogeneous catalyst showed to be more efficient than conventional EF, achieving almost total mineralization of the TC solution (98% of total organic carbon removal) after 360 min under optimum operating conditions. A plausible mineralization pathway for mineralization of TC aqueous solution by OH was proposed based on the identification of different oxidation by-products. Moreover, toxicity tests pointed out that this heterogeneous EF process was able to detoxify the TC solutions.

Kinetics of oxidative degradation/mineralization pathways of the antibiotic tetracycline by the novel heterogeneous electro-Fenton process with solid catalyst chalcopyrite

In-situ X-ray photoelectron spectroscopy studies of water metals and oxides at ambient conditions Ev Vi si ua t w tio ww n Ed .a ct itio iv n eP of DF ac .c tiv om eP DF fo rm So or ftw e d e ar ta e. ils on S Yamamoto 1 , H Bluhm 2 , K Andersson 1,3,6 , G Ketteler 4,7 , H Ogasawara 1 , M Salmeron 4,5 and A Nilsson 1,3 Stanford Synchrotron Radiation Laboratory, P.O.B. 20450, Stanford, CA 94309, USA. Lawrence Berkeley National Laboratory, Chemical Sciences Division, Berkeley, CA 94720, USA. FYSIKUM, Stockholm University, AlbaNova University Center, SE-106 91 Stockholm, Sweden. Lawrence Berkeley National Laboratory, Materials Sciences Division, Berkeley, CA 94720, USA. Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA. E-mail: nilsson@slac.stanford.edu Running head: In-Situ XPS studies of water on metals and oxides at ambient conditions Present address: Center for Individual Nanoparticle Functionality (CINF), Department of Physics, Technical University of Denmark, Fysikvej 312, DK-2800 Kgs. Lyngby, Denmark. Present address: Department of Applied Physics, Chalmers University of Technology, SE-412 96 Goteborg, Sweden. Abstract . X-ray photoelectron spectroscopy (XPS) is a powerful tool for surface and interface analysis, providing the elemental composition of surfaces and the local chemical environment of adsorbed species. Conventional XPS experiments have been limited to ultrahigh vacuum (UHV) conditions due to a short mean free path of electrons in a gas phase. The recent advances in instrumentation coupled with third-generation synchrotron radiation sources enables in-situ XPS measurements at pressures above 5 Torr. In this review, we describe the basic design of the ambient pressure XPS setup that combines differential pumping with an electrostatic focusing. We present examples of the application of in-situ XPS to studies of water adsorption on the surface of metals and oxides including Cu(110), Cu(111), TiO 2 (110) under environmental conditions of water vapor pressure. On all these surfaces we observe a al general trend where hydroxyl groups form first, followed by molecular water adsorption. The importance of surface OH groups and their hydrogen bonding to water molecules in water adsorption on surfaces is discussed in detail.

In-situ X-ray photoelectron spectroscopy studies of water on metals and oxides at ambient conditions

Chalcopyrite hydrometallurgy at atmospheric pressure: 1. Review of acidic sulfate, sulfate–chloride and sulfate–nitrate process options

Current scenario of chalcopyrite bioleaching: a review on the recent advances to its heap-leach technology.

Previous research indicates that coal and coal by-products are a potential source of critical elements including rare earth elements (REE) with estimated amounts in the range of 50 million metric tons. Despite the proven presence of elevated REE concentrations, commercial extraction and recovery have not been realized. This article provides a review of the abundance, mode of occurrence, and recovery methods of rare earth elements in coal and coal by-products. The feasibility of using established REE extraction and recovery technologies is discussed along with issues associated with their use with coal resources.

Yubiao Li

Papers

A review of the structure, and fundamental mechanisms and kinetics of the leaching of chalcopyrite.

Kinetics and roles of solution and surface species of chalcopyrite dissolution at 650 mV

Applications of surface analytical techniques in Earth Sciences

Scanning photoelectron microscopy studies of freshly fractured chalcopyrite exposed to O2 and H2O

Chalcopyrite dissolution: Scanning photoelectron microscopy examination of the evolution of sulfur species with and without added iron or pyrite