Effect of substrate concentration on the bioleaching of heavy metals from sewage sludge

The effect of elemental sulfur concentration on bioleaching of Cu, Zn and Pb and loss of fertilizer value from sewage sludge was investigated in flasks by batch experiments. The results showed that the ultimate pH of sludges with 3—5 g/L of sulfur added was about 1.3 and the production of SO 2- 4 had good correlation with the elemental sulfur concentration. The sensitivity of removal efficiency of metals to sulfur concentration was: Pb>Cu>Zn. The sulfur concentration except for 3—5 g/L had significant effect on the solubilization of Cu, Pb and Zn. The highest solubilization efficiency for sludge with 3 g/L of sulfur was 87.86% for Cu, 32.72% for Pb and 92.14% for Zn, which could make the treated sludge easily meet the metal limitations for land application. The sulfur concentration of 3 g/L was enough for the solubilization of all three heavy metals. The influence of sulfur concentration on solubilization of total nitrogen and potassium from sludge was negligible, but that on solublization of total phosphorus was of great importance. The loss of nitrogen, phosphorus and potassium of sludge with 3 g/L of sulfur by bioleaching was 38.2%, 52.1% and 42.8% respectively, and the sludge still remained satisfactory fertilizer value after bioleaching.

Heavy metals in water bodies purified by suspended substrate of rivers

The equations, which are used to describe the relationships of adsorption quantity (s) , adsorption percent (P \-a), aqueous equilibrium concentration (c) of heavy metal on river suspended substrates and the ratio of adsorbent to water( j ), are developed when heavy metal adsorption on river suspended substrate satisfies with linear adsorption equation. The results, according to the simulation from heavy metal adsorption on suspended substrates of several main Chinese rivers from a previous research report, indicated that these developed equations could describe the linear adsorption processes in practice very well, meanwhile, the adsorption equilibrium constant of adsorbent for heavy metal was an intensity factor regardless of ratio of suspended substrates to water but strongly depended on media's pH. Furthermore, the suspended substrates of Yellow River gave stronger purification ability for Pb than for Cd and Cu. When Cd was purified by different river suspended substrates, it exhibited that the order of their purification ability for Cd was that of Songhuajiang River> Zhujiang Pearl River> Yellow River, which was consistent with their contents of cation exchange capacity(CEC). In addition, we estimated and compared the purification ability of river suspended substrates for cadmium, and the resulting purification percent was 37 64%, 64 58% and 50 98% for Songhuajiang River, Yangtze River and Zhujiang River, respectively.

Exploring the mechanisms of calcium carbonate deposition on various substrates with implications for effective anti-scaling material selection

The unexpected scaling phenomena have resulted in significant damages to the oil and gas industries,leading to issues such as heat exchanger failures and pipeline clogging.It is of practical and fundamental importance to understand the scaling mechanisms and develop efficient anti-scaling strategies.However,the underlying surface interaction mechanisms of scalants(e.g.,calcite)with various substrates are still not fully understood.In this work,the colloidal probe atomic force microscopy(AFM)technique has been applied to directly quantify the surface forces between calcite particles and different metallic substrates,including carbon steel(CR1018),low alloy steel(4140),stainless steel(SS304)and tungsten carbide,under different water chemistries(i.e.,salinity and pH).Measured force profiles revealed that the attractive van der Waals(VDW)interaction contributed to the attachment of the calcium carbonate particles on substrate surfaces,while the repulsive electric double layer(EDL)interactions could inhibit the attachment behaviors.High salinity and acidic p H conditions of aqueous solutions could weaken the EDL repulsion and promote the attachment behavior.The adhesion of calcite particles with CR1018 and4140 substrates was much stronger than that with SS304 and tungsten carbide substrates.The bulk scaling tests in aqueous solutions from an industrial oil production process showed that much more severe scaling behaviors of calcite was detected on CR1018 and 4140 than those on SS304 and tungsten carbide,which agreed with surface force measurement results.Besides,high salinity and acidic p H can significantly enhance the scaling phenomena.This work provides fundamental insights into the scaling mechanisms of calcite at the nanoscale with practical implications for the selection of suitable antiscaling materials in petroleum industries.

Facile electrochemical surface-alloying and etching of Au wires to enable high-performance substrates for surface enhanced Raman scattering

Surface-enhanced Raman Spectroscopy(SERS)is a nondestructive technique for rapid detection of analytes even at the single-molecule level.However,highly sensitive and reliable SERS substrates are mostly fabricated with complex nanofabrication techniques,greatly restricting their practical applications.A convenient electrochemical method for transforming the surface of commercial gold wires/foils into silver-alloyed nanostructures is demonstrated in this report.Au substrates are treated with repetitive anodic and cathodic bias in an electrolyte of thiourea,in a one-pot one-step manner.X-rays absorption fine structure(XAFS)spectroscopy confirms that the AuAg alloy is induced at the surface.The unique AuAg alloyed surface nanostructures are particularly advantageous when served as SERS substrates,enabling a remarkably sensitive detection of Rhodamine B(a detection limit of 10^(-14)M,and uniform strong response throughout the substrates at 10^(-12)M).

Recrystallization Texture and Microstructure of Metal Substrate for Y123 Coated Superconductor

The cube textured pure Ni and non magnetic Cu Ni tapes were obtained by rolling and recrystallization, and these tapes are suitable as substrates of the second generation high temperature superconducting tape. The texture of tapes was studied using Orientation Distribution Function (ODF) and φ scans. The results indicate that sharp cube texture of Cu 0 70 Ni 0.30 and pure Ni was formed at 1000 ℃ and that of Cu 0 85 Ni 0.15 was formed at 900 ℃. The intensities of cube texture differ from each other. Uniform equiaxial crystallites are formed in all the tapes and the size of Cu 0.85 Ni 0.15 is larger than that of Cu 0.70 Ni 0.30 and pure Ni. Annealing twin is formed in Cu 0.85 Ni 0.15 and Cu 0.70 Ni 0.30 .

Study on the Heavy Metals Removal Efficiencies of Constructed Wetlands with Different Substrates

In this study constructed wetlands (CWs) were used to remove three heavy metals (Zn, Cu and Pb). The two tested substrates were made of coke and gravel, respectively. First order dynamic model was appropriate to describe removing of Zn and Cu. The experimental results showed that first dynamic removal rate constants of Zn in CWs with coke and gravel were 0.2326 h-1 and 0.1222 h-1, respectively. And those of Cu in CWs with coke and gravel were 0.2017 h-1 and 0.3739 h-1. However, removal efficiencies of Pb in the coke system and the gravel system were within 95-99%, so the first order dynamic model failed to fit the experimental data because the hydraulic resident times of Pb did not affect outlet concentration of Pb. From the removal rate constants, it is found that the coke and gravel system have different absorption efficiencies of heavy metal pollutants. Therefore, it is suggested that the removal efficiencies of heavy metals are influenced by the choice of substrates to some extent.

A Pore-Forming Strategy Toward Porous Carbon-Based Substrates for High Performance Flexible Lithium Metal Full Batteries

Self-standing carbon-based substrates with satisfied structural stability and property adjustability have promising applications in flexible lithium(Li)metal batteries(FLMBs).Current strategies for modifying carbon materials are normally carried out on powder carbon,and very few of them are suitable for self-standing carbon substrates.Herein,a pore-forming strategy based on the redox chemistry of metallic oxide nanodots is developed to prepare two porous carbon substrates for anode and cathode.Starting with cotton cloth,the resulting hollow carbon fibers substrate with nanopores effectively prevents from Li dendrites formation and large volume change in lithium metal anode(LMA).Simulations indicate that the porous structure leads to homogeneous ion flux,Li-ion concentration,and electric field during Li deposition.Li symmetrical cell based on this substrate remains stable for 8300 h with an ultralow voltage hysteresis of 9 mV.Via a similar route,porous carbon cloth substrate is obtained for subsequently seeding V_(2)O_(5)nanowires to prepare the cathode.The assembled FLMBs pouch cell delivers a capacity of 8.2 mAh with a high capacity retention of~100%even under dramatic deformation.The demonstrated strategy has far-reaching potential in preparing free-standing porous carbon-based materials for flexible energy storage devices.

In-situ design and construction of lithium-ion battery electrodes on metal substrates with enhanced performances：A brief review

For the ever-growing demand of advanced lithium-ion batteries, it is highly desirable to grow self-supported micro-/nanostructured arrays on metal substrates as electrodes directly. The in-situ growth of electrode materials on the conducting substrates greatly simplifies the electrode fabrication process without using any binders or conductive additives. Moreover, the well-ordered arrays closely connected to the current collectors can provide direct electron transport pathways and enhanced accommodation of strains arisen from lithium ion lithiation/delithiation. This article summarizes our recent work on design and construction of lithium-ion battery electrodes on metal substrates. An aqueous solution-based process and a microemulsion-mediated process have been respectively presented to control the kinetic and thermodynamic processes for the micro-/nanostructured array growth on metal substrates, with particular attention to CuO nanorod arrays and microcog arrays successfully prepared on Cu foil substrates. They can be directly used as binder-free electrodes to build advanced lithium-ion batteries with high energy, high safety and high stability.

An in-situ generated Bi-based sodiophilic substrate with high structural stability for high-performance sodium metal batteries

Sodium(Na)metal anode exhibits a potential candidate in next-generation rechargeable batteries owing to its advantages of high earth abundance and low cost.Unfortunately,the practical development of sodium metal batteries is inherently plagued by challenges such as the side reactions and the growth of Na dendrites.Herein we report a highly stable Bi-based“sodiophilic”substrate to stabilize Na anode,which is created by in-situ electrochemical reactions of 3D hierarchical porous Bi_(2)MoO_(6)(BMO)microspheres.BMO is initially transformed into the Bi“nanoseeds”embedded in the Na-Mo-O matrix.Subsequently,the Bi nanoseeds working as preferential nucleation sites through the formation of BiNa alloy enable the non-dendritic Na deposition.The asymmetric cells based on such BMO-based substrate can deliver a long-term cycling for 600 cycles at a large capacity of 4 m Ah cm^(-2) and for 800 cycles at a high current density of 10 m A cm^(-2).Even at a high depth of discharge(66.67%),the Na-predeposited BMO(Na@BMO)electrodes can cycle for more than 1600 h.The limited Na@BMO anodes coupled with the Na_(3)V_(2)(PO_(4))_(3) cathodes(N/P ratio of 3)in full cells also show excellent electrochemical performance with a capacity retention of about 97.4%after 1100 cycles at 2 C.

Relation of Deposition Condition with Microstructure of YBCO Film and YSZ Buffer Layer on Metallic Substrate

icrostructures of two Yba_2Cu_3O_(7-y) (YBCO) film deposited on metal substrate (HastelloyC) with yttriastabilized zirconia (YSZ) buffer layer were studied comparatively. Relation of microstructure with deposition condition was also been discussed. The YSZ buffer layer with a low depositing rate is dense, even, textured and wellbonded to the substrate. On the contrary, the YSZ layer deposited with a high rate is loose and bonded badly to the substrate. Property and surface grain size of YBCO film are related to the substrate temperature (Ts) in the deposition process.

Gas permeation properties of a metallic ion-cross-linked PIM-1 thin-film composite membrane supported on a UV-cross-linked porous substrate

Metallic ion-cross-linked polymer of intrinsic microporosity(PIM-1) thin-film composite(TFC) membranes supported on an ultraviolet(UV)-cross-linked porous substrate were fabricated. The UV-cross-linked porous substrate was prepared via polymerization-induced phase separation. The PIM-1 TFC membranes were fabricated via a dip-coating procedure. Metallic ion-cross-linked PIM-1 TFC membranes were fabricated by hydrolyzing the PIM-1 TFC membrane in an alkali solution and then cross-linking it in a multivalent metallic ion solution. The pore size and porous structures were evaluated by low-temperature N_2 adsorption–desorption analysis. The membrane structure was investigated by field-emission scanning electron microscopy. The effects of heat treatment and pore-forming additives on the gas permeance of the UV-cross-linked porous substrate are reported. The effects of different pre-coating treatments on the gas permeance of the metallic ion-cross-linked PIM-1 TFC membrane are also discussed. The metallic ion-crosslinked PIM-1 TFC membrane displayed high CO_2/N_2 selectivity(23) and good CO_2 permeance(1058 GPU).

CATALYTIC ACTIVITIES OF SUBSTRATE METALS IN A Ni-B-SiC ELECTROLESS COMPOSITE BATH

The catalytic activities of different substrate metals in Ni-B-SiC electroless composite bath was investigatedby means of measuring stationary potentials,potential-time curves and EPMA.The mechanism of electrolessplating taking place in the substrate metals at initial stage was investigated.Experimental results showed:(1)Inaddition to the stationary potential of the substrate metal and the temperature of the bath,the change of the sur-face state of metal,e.g.,its passivity,is one of the factors for deciding catalytic activity of a substrate metal.(2)the transition time is helpful in determines the degree of catalytic activity.(3)If the substrate metals possesscatalytic activity,the coating rates of electroless plating are mostly equal.

Microstructure of YBCO Superconducting Film on Metal Substrate with YSZ Buffer Layer

Microstructures of YBa_2Cu_3O_(7-y)(YBCO) film on flexible metal substrate with yttriastabilized zirconia(YSZ) buffer layer prepared by magnetron sputtering technique have been studied in this paper using transmission electron microscopy(TEM). A critical temperature(Tc) and a critical current density(Jc) of the YBCO film are 91 K and 2×103 A/cm2 at 77 K, 0 T respectively. Bonded steadfastly to the substrate of nickel alloy(HastelloyC), the dense, even and textured YSZ layer with fine crystal grains is about 12 μm thick. With an uneven thickness of about 500 nm, the YBCO layer is sometimes weakbonded to the YSZ layer. Impurities which occasionally led to cracks were observed at the YSZ/YBCO interface.

Stacked lateral double-diffused metal–oxide–semiconductor field effect transistor with enhanced depletion effect by surface substrate

A stacked lateral double-diffused metal–oxide–semiconductor field-effect transistor(LDMOS) with enhanced depletion effect by surface substrate is proposed(ST-LDMOS), which is compatible with the traditional CMOS processes. The new stacked structure is characterized by double substrates and surface dielectric trenches(SDT). The drift region is separated by the P-buried layer to form two vertically parallel devices. The doping concentration of the drift region is increased benefiting from the enhanced auxiliary depletion effect of the double substrates, leading to a lower specific on-resistance(Ron,sp). Multiple electric field peaks appear at the corners of the SDT, which improves the lateral electric field distribution and the breakdown voltage(BV). Compared to a conventional LDMOS(C-LDMOS), the BV in the ST-LDMOS increases from 259 V to 459 V, an improvement of 77.22%. The Ron,sp decreases from 39.62 m?·cm^2 to 23.24 m?·cm^2 and the Baliga's figure of merit(FOM) of is 9.07 MW/cm^2.

Trinuclear Metal Complexes Based on 1,10-Phenanthroline Derivates as Catalysts for Cleavage of a RNA-Model Substrate

Two multidentate ligands 2,9-di[6＇-（2″-hydroxyl-3″-methoxyphenyl）-n-2＇,5＇-diazahexyl]-1,10-phenanthroline（LA）and 2,9-di（6＇-α-phenol-n-2＇,5＇-diazahexyl）-1,10-phenanthroline（LB）were synthesized and fully characterized.Protonation of the ligands and the stability of the complexes of the ligands with divalent metal ions were investigated.The trinuclear metal complexes [Cu（Ⅱ）and Zn（Ⅱ）] of the ligands were studied,as catalysts,for the transphosphorylation of the RNA-model substrate 2-hydroxypropyl-p-nitrophenyl phosphate（HPNP）.The second-order rate constants of HPNP-hydrolysis catalyzed by M3L and M3LH-1 were obtained,which indicated that Zn3LBH-1 was the most efficient catalyst among them.The proposed mechanisms included the activation of the substrate via binding to the metal ions and intramolecular nucleophilic attack by the deprotonated C2-hydroxyl of HPNP.

Thickness distribution of large scale metallic sheet by EB-PVD on rotating substrate

A two-dimensional kinetic Monte-Carlo(KMC) method was used to approach the thickness distribution of large scale metallic sheet deposited by electron beam physical vapor deposition(EB-PVD) on rotating substrate. The KMC model involves incident atom attachment, adatom diffusion and adatom detachment. The effective deposition rate and effective incident angle along substrate radial were studied as influencing factors of sheet thickness distribution. The KMC simulation results indicate that incident angle is a very important factor to affect the sheet thickness distribution as well as theory deposition mass. The experiments results show that the KMC model can predict the thickness distribution of large scale sheet deposited by EB-PVD on rotating substrate.

Improved Semipolar(11(2|-)2) GaN Quality Grown on m-Plane Sapphire Substrates by Metal Organic Chemical Vapor Deposition Using Self-Organized SiN_x Interlayer

The effect of a self-organized SiNs interlayer on the defect density of （1122） semipolar GaN grown on 7n-plane sapphire is studied by transmission electron microscopy, atomic force microscopy and high resolution x-ray diffrac- tion. The SiNx interlayer reduces the c-type dislocation density from 2.5 ×10^10 cm^-2 to 5 ×10^8 cm 2. The SiNx interlayer produces regions that are free from basal plane stacking faults （BSFs） and dislocations. The overall BSF density is reduced from 2.1×10^5 cm-1 to 1.3×10^4 cm^-1. The large dislocations and BSF reduction in semipolar （1122） GaN with the SiNx, interlayer result from two primary mechanisms. The first mechanism is the direct dislocation blocking by the SiNx interlayer, and the second mechanism is associated with the unique structure character of （1122） semipolar GaN.

Fabrication of InAlGaN/GaN High Electron Mobility Transistors on Sapphire Substrates by Pulsed Metal Organic Chemical Vapor Deposition

Nearly lattice-matched InAIGaN/GaN heterostructure is grown on sapphire substrates by pulsed metal organic chemical vapor deposition and excellent high electron mobility transistors are fabricated on this heterostructure. The electron mobility is 1668.08cm2/V.s together with a high two-dimensional-electron-gas density of 1.43 × 10^13 cm-2 for the InAlCaN/CaN heterostructure of 2Onto InAlCaN quaternary barrier. High electron mobility transistors with gate dimensions of 1 × 50 μm2 and 4μm source-drain distance exhibit the maximum drain current of 763.91 mA/mm, the maximum extrinsic transconductance of 163.13 mS/mm, and current gain and maximum oscillation cutoff frequencies of 11 GHz and 21 GHz, respectively.

Improved electrochemical hydrogen storage properties of Mg-Y thin films as a function of substrate temperature

Pd-capped Mg78Y22 thin films have been prepared by direct current magnetron co-sputtering system at different substrate temperatures and their electrochemical hydrogen storage properties have been investigated.It is found that rising substrate temperature to 60 ℃ can coarsen the surface of thin film,thus facilitating the diffusion of hydrogen atoms and then enhancing its discharge capacity to 1725 mAh·g-1.Simultaneously,the cyclic stability is effectively improved due to the increased adhesion force between film and substrate as a function of temperature.In addition,the specimen exhibits a very long and flat discharge plateau at about —0.67 V,at which nearly 60%of capacity is maintained.The property is favorable for the application in metal hydride/nickel secondary batteries.The results indicate that rising optimal substrate temperature has a beneficial effect on the electrochemical hydrogen storage of Mg-Y thin films.

Tuning the alignment of pentacene on copper substrate by annealing-assistant surface functionalization

Controlling the alignment and packing structure of organic molecules on solid substrate surfaces at molecule level is essential to develop high-performance organic thin film(OTF)devices.Pentacene,which is a typical p-type semiconductor material usually adopts lying-down geometry on metal substrates owning toπ-d coupling between pentacene and metal substrates.However,in this study,we found that pentacene molecules can be adsorbed on an anneal-treated Cu(111)surface with their long axis perpendicular to substrate surface.Highly ordered single-layer pentacene film with stand-up molecular geometry was achieved on this substrate.It was found that the functionalization of Cu surface with C=O groups due to annealing treatment should be accounted for standing-up geometry of pentacene on Cu substrate.This observation shed light on the tuning of the alignment and packing structure of organic molecules.