Multicycle Performance of CaTiO Decorated CaO-Based CO Adsorbent Prepared by a Versatile Aerosol Assisted Self-Assembly Method.

Calcium oxide (CaO) is a promising adsorbent to separate CO from flue gas. However, with cycling of carbonation/decarbonation at high temperature, the serious sintering problem causes its capture capacity to decrease dramatically. A CaTiO-decorated CaO-based CO adsorbent was prepared by a continuous and simple aerosol-assisted self-assembly process in this work.

Nanoflaky MnO2/functionalized carbon nanotubes for supercapacitors: an in situ X-ray absorption spectroscopic investigation.

The surfaces of acid- and amine-functionalized carbon nanotubes (C-CNT and N-CNT) were decorated with MnO2 nanoflakes as supercapacitors by a spontaneous redox reaction. C-CNT was found to have a lower edge plane structure and fewer defect sites than N-CNT. MnO2/C-CNT with a highly developed surface area exhibited favorable electrochemical performance.

Hexavalent chromium removal from near natural water by copper-iron bimetallic particles.

The reduction of hexavalent chromium (Cr(VI)) by zero-valent iron (ZVI) is self-inhibiting in near natural groundwater because insulating Fe(III)-Cr(III) (oxy)hydroxide film forms on the ZVI surface during the reaction. This study tries to overcome this deficiency by coating the surface of ZVI with copper to form copper-iron bimetallic particles. The Cr(VI) removal rate by ZVI rose significantly after the copper coating was applied.

Selective decomposition of aqueous nitrate into nitrogen using iron deposited bimetals.

In the case of the reduction of nitrate in groundwater, the problem is how to convert nitrate [N(+V)] selectively to nontoxic dinitrogen [N(O)] and not to completely reduced ammonia [N(-III)]. Unfortunately, near 100% of the total nitrogen in nitrate is reductively converted to ammonia using naked zerovalent iron (ZVI) thus far reported. In this study, deposition of noble metals (Pt, Pd, and Au) and Cu on iron surface to offer favorable pathways for nitrate reduction was fabricated using either the complete mixing orthe successive method with spontaneous redox reactions.

Supported Pd/Sn bimetallic nanoparticles for reductive dechlorination of aqueous trichloroethylene.

A Pd/Sn bimetallic nanoparticles resin (nano-Pd/Sn/resin) was successfully synthesized for reductive transformation of aqueous trichloroethylene (TCE). The physicochemical properties of the prepared resin were characterized using scanning electron microscopy, energy dispersive X-ray spectroscopy, N(2) isothermal sorption at and X-ray photospectroscopy. The surface-area-normalized rate constants (k(SA)) of Sn particles in the nanoscale range (50-100 nm) were 4.

Photocatalytic oxidation of aqueous ammonia over microwave-induced titanate nanotubes.

Characterizations of microwave-induced titanate nanotubes (NaxH(2-x)Ti3O7, TNTs) were conducted by the determinations of specific surface area (S(BET)), X-ray diffraction (XRD), X-ray photoelectron spectroscopic (XPS), ionic coupled plasma-atomic emission spectrometry(ICP-AES), scanning electron microscopy/ energy dispersive X-ray (SEM/EDX), and high-resolution transmission electron microscopy (HR-TEM). The applied level of microwave irradiation during the fabrication process is responsible for both the intercalation intensity of Na atoms into TNTs and the type of crystallization phase within TNTs, which dominate the efficiency of photocatalytic NH3/NH4+. A pure TNT phase presents no powerful ability toward photocatalytic NH3/ NH4+, while the photocatalytic efficiency can be enhanced with the presence of a rutile phase within TNTs.

Size effect in reactivity of copper nanoparticles to carbon tetrachloride degradation.

Surface area-normalized rate constants (k(SA)) of reaction between metallic nanoparticles and reducible contaminants, such as chlorinated hydrocarbons, heavy metals, and nitrate, have been reported to be dramatically increased as compared to that of commercial metallic powder. However, k(SA) for individual pollutants in previously published data vary by as much as 1-2 orders of magnitude and much of this variability is due to the effect of various sizes. The size dependence of the reactivity of nanoparticles is not yet fully understood; however, yielding nanoparticles with uniform size and without agglomeration during the period of reaction would demonstrate the effect of varying particle size.

Effect of precursor concentration on the characteristics of nanoscale zerovalent iron and its reactivity of nitrate.

Differing precursor concentrations, 1.0, 0.1, and 0.

Effects of iron surface pretreatment on kinetics of aqueous nitrate reduction.

Using hydrogen gas at 400 degrees C to activate iron surface was proposed to remove nitrate (40 mg NL(-1)) in a HEPES buffer solution at pH value between 6.5 and 7.5.

Chemical reduction of an unbuffered nitrate solution using catalyzed and uncatalyzed nanoscale iron particles.

Uncatalyzed and catalyzed nanoscale Fe(0) systems were employed for the denitrification of unbuffered 40 mgN L(-1) nitrate solutions at initial neutral pH. Compared to microscale Fe(0) (<100 mesh), the efficiency and rate of nitrate removal using uncatalyzed and catalyzed nano-Fe(0) were highly promoted, in which the maximum promoted rate was obtained using copper-catalyzed nano-Fe(0) (nano-Cu/Fe). Nitrate first-order degradation rate constants (k(obs)) decreased significantly (>70%) with aged nano-Fe(0) and aged nano-Cu/Fe, and were recovered with NaBH(4) as reductants at levels of about 85 and 75%, respectively.

Degradation of aqueous carbon tetrachloride by nanoscale zerovalent copper on a cation resin.

Nanoscale zerovalent copper supported on a cation resin was successfully synthesized to enhance the removal of carbon tetrachloride (CCl(4)) from contaminated water. The use of the cation resin as a support prevents the reduction of surface area due to agglomeration of nanoscale zerovalent copper particles. Moreover, the cation resin recycles the copper ions resulting from the reaction between CCl(4) and Cu(0) by simultaneous ion exchange.

Dechlorination of trichloroethylene in aqueous solution by noble metal-modified iron.

Bimetallic particles are extremely interesting in accelerating the dechlorination of chlorinated organics. Four noble metals (Pd, Pt, Ru and Au), separately deposited onto the iron surface through a spontaneous redox process, promoted the TCE dechlorination rate, and the catalytic activity of the noble metal followed the order of Pd>>Ru>Pt>Au. This order was found to be dependent on the concentrations of adsorbed atomic hydrogen, indicating that the initial reaction was cathodically controlled.