Cost-effective Recovery Research Articles

The modeling of gold recovery from tetrachloroaurate wastewater using a microbial fuel cell

In this study, tetrachloroaurate as an electron acceptor of a microbial fuel cell (MFC) has been studied to discover the parameters that affect the cost-effective recovery of gold. The modeling and equations for calculating the maximum actual efficiency and electrochemical impedance spectroscopic internal resistance of the MFC were also developed. The maximum power density (Pmax) of 6.58W/m2 with a fill factor of 0.717 was achieved for 60mL volumes of 2000ppm Au(III) catholyte and 12.2mM acetate anolyte, respectively. The Pmax can also be predicted simply by measuring Rint by EIS. Additionally, the maximum actual MFC efficiency of about 57% was achieved, and the recovery efficiency of Au and the remaining concentration reached 99.89±0.00% and 0.22±0.00ppm, respectively, for an Au(III) concentration of 200ppm. The anodic concentration polarization quenching of the MFC strongly supports a mediator mechanism for the electron transfer from the microorganism to the anode.

Facile fabrication of magnetically separable graphitic carbon nitride photocatalysts with enhanced photocatalytic activity under visible light

Because of their potential application in the conversion of solar energy to chemical energy, the development of semiconductor photocatalysts that have high reactivity under visible light has received great attention. In the present work, we illustrate the design and fabrication of magnetically separable polymeric carbon nitride photocatalysts, i.e. Fe2O3/g-C3N4 composite photocatalysts, a novel type of visible light driven photocatalyst with a cost-effective recovery manner. The obtained Fe2O3/g-C3N4 composite catalysts with different Fe2O3 contents were characterized by powder X-ray diffraction (PXRD), high-resolution transmission electron microscopy (HRTEM), UV-vis diffuse reflection spectroscopy (DRS), vibration sample magnetometry (VSM) and thermogravimetric analysis (TGA). The saturation magnetization at 300 K varies from 0.37 to 1.56 emu g−1, depending on the different Fe2O3 contents (2.8–11.6 wt%) in the Fe2O3/g-C3N4 composites, clearly indicating the excellent magnetic separation characteristics of the as-prepared photocatalysts. Remarkably, the photocatalytic activity of the magnetic Fe2O3/g-C3N4 photocatalysts under visible light irradiation was increased up to 1.8 times for the photodegradation of Rhodamine B (RhB) under visible light irradiation compared with the conventional pure g-C3N4 photocatalyst. A possible mechanism for the enhanced photocatalytic activity of the Fe2O3/g-C3N4 composite photocatalyst was also proposed to guide the further improvement of their photocatalytic activity.

A focus on pressure-driven membrane technology in olive mill wastewater reclamation: state of the art

Direct disposal of the heavily polluted effluent from olive oil industry (olive mill wastewater, OMW) to the environment or to domestic wastewater treatment plants is actually prohibited in most countries, and conventional treatments are ineffective. Membranes are currently one of the most versatile technologies for environmental quality control. Notwithstanding, studies on OMW reclamation by membranes are still scarce, and fouling inhibition and prediction to improve large-scale membrane performance still remain unresolved. Consequently, adequately targeted pretreatment for the specific binomium membrane-feed, as well as optimized operating conditions for the proper membranes, is today's challenge to ensure threshold flux values. Several membrane materials, configurations and pore sizes have been elucidated, and also different pretreatments including sedimentation, centrifugation, biosorption, sieving, filtration and microfiltration, various types of flocculation as well as advance oxidation processes have been applied so far. Recovery of potential-value compounds, such as a variety of polyphenols highlighting oleuropein and hydroxytyrosol, has been attempted too. All this research should constitute the starting point to proceed with OMW purification beyond recycling for irrigation or depuration for sewer discharge, with the aim of complying with standards to reuse the effluent in the olive oil production process, together with cost-effective recovery of added-value compounds.

Reactive Extraction of Propionic Acid Using Tri-n-octylamine

Propionic acid has been received increasing attention due to its various usages as an antifungal agent in food and a chemical in the production of several chemical products. In order to develop an alternative production process of propionic acid such as fermentation of glycerol, the cost effective recovery process of propionic acid from its fermentation broth is needed. Differently from conventional physical extraction, long chain amine (TOA)-based extraction is the separation process using reactions between amine and materials extracted. The equilibrium distribution of propionic acid increased with amine concentration and decreased with increase of n-heptane composition in mixed diluents. From the loading values with TOA concentrations, it was found that the stoichiometries of acid-amine-1-octanol complex were (1,1) and (1,1,1). From this study, amine-based extraction can be promising separation process for the recovery of propionic acid.

Selective adsorption of HMF on porous carbons from fructose/DMSO mixtures

5-Hydroxymethylfurfural (HMF) is an important intermediate chemical for producing valuable chemicals from biomass and can be synthesized with high yield from the dehydration of fructose in dimethyl sulfoxide (DMSO). Here, we investigate the room temperature separation of HMF from DMSO for a cost effective recovery of the product from the reaction mixture that contains unreacted fructose. BP2000, Norit1240, BP1300, BP880 and XC72 were tested as sorbents. BP2000 and Norit1240 exhibit selectivity and capacity for HMF. Depending on relative concentrations, HMF/fructose separation factors up to 45 for BP2000 and 13 for Norit1240 were obtained. Under certain conditions, by increasing the concentration of fructose in the solution, HMF adsorption increased significantly.

Cost-Effective Energy Recovery Circuit for Plasma Display

A cost-effective energy recovery (ER) circuit for plasma display is proposed in this paper. Besides main full-bridge sustain switches, the ER circuit should be included in the sustain driver for plasma display to reduce the power loss. The proposed ER circuit consists of four diodes and a single external inductor. Due to a simpler structure than the conventional ER circuit, the efficiency can be improved and the overall cost is reduced. Theoretical analysis and performance of the proposed ER circuit were verified on an experimental prototype operating at 200 kHz switching frequency

Recovering Kiwifruit Pruning Residues for Biomass Production

Three systems for recovering kiwifruit pruning residues were compared for their cost-effectiveness. The systems were a shredder with a built-in dumping container; a shredder with drop-down re-usable bins, of the type normally used for fruit collection, working with a dedicated bin-collection system; and a round baler equipped with an add-on bale storage unit. All systems were light enough to be towed or carried behind a compact vineyard tractor. Harvesting and processing productivity, including all delays, ranged from 1.8 to 3.7 tonnes per scheduled machine hour (SMH). After standardization, calculated recovery cost varied between 8.4 and 28.6 Euros t-1 for the residue delivered at the field edge. The shredder with a built-in dumping container emerged as the best performer, favored because of a faster pick-up and a more efficient single-pass work mode. Overall, this system is simpler, more productive, and offers the lowest processing cost. The annual utilization of all the dedicated recovery implements tested should at least be 50 ha year-1 (approx. 500 t year-1) in order to obtain acceptable cost results. Kiwifruit orchards offer a very high residue yield, about four times higher than vineyards and olive tree groves. This favors cost-effective recovery and makes them a significant potential source of energy biomass, the exploitation of which may also simplify residue management and improve plant health conditions.

Simultaneous clock recovery and dispersion, OSNR monitoring for 112-Gbit/s NRZ-DQPSK using frequency down-conversion electro-optical phase-locked loop

A cost effective clock recovery scheme simultaneously providing signal performance monitoring is proposed for high speed electrical time domain multiplexing (ETDM) transmission systems to release the bandwidth requirement on the involved electrical devices. In the scheme, we first convert the clock frequency down in the optical domain using electroptic modulation, and then extract the clock with a phase locked loop (PLL) after photo-detection. All the devices involved are operated at frequencies lower than half of the symbol rate. Furthermore, we use a quadrature phase detector in the PLL to create a monitor signal which characterizes the transmitted signal performance in terms of optical-to-noise ratio (OSNR) and accumulated chromatic dispersion (ACD). This scheme is applied to a 112-Gbit/s none-return-to-zero (NRZ) differential quadrature phase shift keying (DQPSK) system. Experimental results show that the clock can be recovered in a dispersion range of -40 to 40 ps/nm, and the evaluated OSNR, over a range of 18~36 dB, has a deviation smaller than 1 dB compared to the measured one based on the optical spectrum method. The bit error ratio remains below 10(-9) for 12 hours in the back-to-back case and 2 hours after transmission over 100-km standard single mode fiber (SSMF).

ChemInform Abstract: Zeolite H‐BEA Catalyzed Multicomponent Reaction: One‐Pot Synthesis of Amidoalkyl Naphthols — Biologically Active Drug‐Like Molecules.

AbstractCompared to conventional methods employing solvents, the introduced synthesis under solvent‐free conditions has the advantages of shorter reaction times, simple work‐up, environmental friendliness, excellent yields, cost effective recovery and reusability of catalyst for a number of times without significant loss of activity.

Production and quality of biomass fuels from mechanized collection and processing of vineyard pruning residues

Vineyards cover about eight millions of hectares worldwide and their annual pruning generates a large amount of ligno-cellulosic biomass, potentially available for industrial and energy use. Commercial pruning residue harvesters are now available, which may allow cost-effective recovery. The study aimed at determining the quantity and the quality of pruning residues potentially derived from vineyard management. Data were obtained from 17 fields in Northern and Central Italy. Fields were harvested with seven different machines. The experimental design adapted to the necessities of field trials, but was adequate for testing the main sources of variability. Net residue yield varies around 1 oven dry tonne per hectare, with minor differences between grape varietals and harvesting technologies. Losses are still high, and are generally related to ineffective management techniques. Moisture content at harvest varies between 40% and 45%, whereas the higher heating value is slightly lower than that of forest fuels. Comminuted vineyard residues are unsuitable for firing residential boilers, due to the frequent presence of oversize and/or undersize particles. The application of pesticides does not result in any significant contamination with noxious chemicals, because these products are almost completely weathered before residues are recovered. In wine-producing regions, the recovery of vineyard pruning residue may represent a substantial source of industrial bio-fuel.

Incorporating rework into construction schedule analysis

Rework has been a primary cause of cost and schedule overruns in large construction projects. While several research efforts have analyzed the causes and effects of rework and provided guidelines to reduce rework, almost no research exists to analyze the impact of rework timing and quantity on schedule delays and to support decisions on cost effective recovery. This research presents a quantitative mechanism for schedule analysis considering rework. The mechanism has three aspects: (1) a new schedule representation of rework magnitude as negative percentage complete for affected activities, documented on the specific date on which the rework is detected; (2) a modified daily-windows delay analysis to apportion project delays among the responsible parties; and (3) an optimization technique for determining the least costly corrective action strategy that recovers project delays. The proposed approach is applied to a case study to demonstrate its ability to consider rework impact, in combination with other progress events by other project parties. This research offers an innovative quantitative approach to consider rework timing and amount in delay analysis and corrective action optimization.

How safe are adolescents at Alcoholics Anonymous and Narcotics Anonymous meetings? A prospective investigation with outpatient youth

Alcoholics Anonymous (AA) and Narcotics Anonymous (NA) have proven to be cost-effective recovery resources for adults and also appear helpful for youth. However, anecdotal concerns about adolescents' safety at meetings have dampened enthusiasm regarding youth participation. Unfortunately, little information exists to evaluate such concerns. Outpatients ( N = 127; 24% female) were assessed at intake and at 3, 6, and 12 months regarding perceived safety at AA/NA, experience of negative incidents, and reasons for nonattendance/discontinuation. By 12-month follow-up, 57.5% reported some AA/NA attendance with a combined lifetime exposure of 5,340 meetings. Of these, 21.9% reported at least one negative experience, which was more common among NA than AA attendees. Overall, youth reported feeling very safe at meetings, and ratings did not differ by age or gender. Reasons for discontinuation or nonattendance were unrelated to safety or negative incidents. Weighing risks against documented benefits, these preliminary findings suggest that referral to AA/NA should not be discouraged, but, similar to adults, youth experiences at meetings should be monitored.

Implementing a Cost-Effective RO Concentrate Treatment and Recovery Approach at the Leo J. Vander Lans Water Treatment Facility

Implementing a Cost-Effective RO Concentrate Treatment and Recovery Approach at the Leo J. Vander Lans Water Treatment Facility

Can 12-step group participation strengthen and extend the benefits of adolescent addiction treatment? A prospective analysis

Background Despite advances in the development of treatments for adolescents with substance use disorders (SUD), relapse remains common following an index treatment episode. Community continuing care resources, such as Alcoholics Anonymous (AA) and Narcotics Anonymous (NA), have been shown to be helpful and cost-effective recovery resources among adults. However, little is known about the clinical utility and effectiveness of AA/NA for adolescents, despite widespread treatment referrals. Method Adolescents ( N = 127; 24% female, 87% White, M age = 16.7 years) enrolled in a naturalistic, prospective study of community outpatient treatment were assessed at intake, and 3 and 6 months later using a battery of standardized and validated measures. Results Just over one-quarter of youth attended AA/NA meetings during the first 3 months, which was predicted by a goal of abstinence, prior AA/NA attendance, and prior SUD treatment experiences. Controlled multiple regression analyses revealed an independent effect of AA/NA on abstinence, in both contemporaneous and lagged models, which persisted over and above the effects of pre-treatment AA/NA attendance, prior treatment, self-efficacy, abstinence goal, and concomitant outpatient treatment. Conclusions Results suggest that, similar to findings comparing adult outpatients to inpatients, AA/NA participation is less common among less severe adolescent outpatients. Nonetheless, attendance appears to strengthen and extend the benefits of typical community outpatient treatment. Given the dramatic increase in rates of substance use among same-aged peers in the population at this life-stage, and the relative dearth of abstainers and recovery-specific supports, these resources may provide a concentrated cost-effective social recovery resource for young people.

High yield combustion synthesis of nanomagnesia and its application for fluoride removal

We describe a novel combustion synthesis for the preparation of Nanomagnesia (NM) and its application in water purification. The synthesis is based on the self-propagated combustion of the magnesium nitrate trapped in cellulose fibers. Various characterization studies confirmed that NM formed is crystalline with high phase purity, and the particle size varied in the range of 3–7 nm. The fluoride scavenging potential of this material was tested as a function of pH, contact time and adsorbent dose. The result showed that fluoride adsorption by NM is highly favorable and the capacity does not vary in the pH range usually encountered in groundwater. The effects of various co-existing ions usually found in drinking water, on fluoride removal were also investigated. Phosphate was the greatest competitor for fluoride followed by bicarbonate. The presence of other ions studied did not affect the fluoride adsorption capacity of NM significantly. The adsorption kinetics followed pseudo-second-order equation and the equilibrium data are well predicted by Frendlich equation. Our experimental evidence shows that fluoride removal happened through isomorphic substitution of fluoride in brucite. A batch household defluoridation unit was developed using precipitation–sedimentation–filtration techniques, addressing the problems of high fluoride concentration as well as the problem of alkaline pH of the magnesia treated water. The method of synthesis reported here is advantageous from the perspectives of small size of the nanoparticle, cost-effective recovery of the material and improvement in the fluoride adsorption capacity.

Recovery of Depleted Uranium Fragments from Soil

A "proof of concept" was conducted to determine the effectiveness of a survey method for cost-effective recovery of depleted uranium (DU) fragments from contaminated soil piles at Sandia National Laboratories. First, DU fragments ranging from less than a gram up to 48 g were covered by various thicknesses of soil and used for detector efficiency measurements. The efficiencies were measured for three different sodium iodide detectors: a 5.1-cm by 5.1-cm (2-inch by 2-inch) detector, a 7.6-cm by 7.6-cm (3-inch by 3-inch) detector, and a Field Instrument for the Detection of Low Energy Radiation (FIDLER) detector. The FIDLER detector was found to be superior to the other detectors in each measurement. Next, multiple 7.6-cm (3-inch) layers of soil, taken from the contaminated piles, were applied to a clean pad of soil. Each layer was scanned by an array of eight FIDLER detectors pulled by a tractor. The array, moving 10.2 to 12.7 cm s(-1) (4 to 5 inches per second), automatically recorded radiation count data along with associated detector coordinates at 3-s intervals. The DU fragments were located and identified with a handheld system consisting of a FIDLER detector and a positioning system and then removed. After DU removal, the affected areas were re-scanned and a new lift of contaminated soil was applied. The detection capability of the system as a function of DU fragment mass and burial depth was modeled and determined to be sufficient to ensure that the dose-based site concentration goals would be met. Finally, confirmation soil samples were taken from random locations and from decontaminated soil areas. All samples had concentrations of U that met the goal of 400-500 pCi g(-1).

Compound OD Cycles for a Wide Variety of Survivability Policies in Transport Networks

Converged telecommunication networks, which simultaneously support a growing variety of services through a common network infrastructure, are aimed at significantly reducing network expenditures. This trend has encouraged the development of a unified network paradigm capable of supporting a wide variety of cost-effective recovery solutions, each of which may cope differently with fiber cuts and nodal equipment failures in order to satisfy service-dependent requirements. Expansion of the Origin-Destination (OD) Cycles approach is used to meet that challenge by offering ten different policies for survivability and their relative performance measures in terms of consumption of network resources and the resulting times of recovery. For practical purposes the scope of failure scenarios is limited to single and double-network failures only, even though the approach suggested is generic and can basically address even more complex events. Three test networks are extensively analyzed to demonstrate the paradigm developed and to present some useful observations about the relative positioning of the policies considered for survivability

非在来型石油天然ガス開発技術

While conventional oil and gas production is expected to hit a peak in dozens of years, the world still requires hydrocarbons as the main source of energy. The need to fill the gap between supply and demand, and the recent high oil price, have aroused enthusiasm for unconventional oil and gas. But, the development of them is, full of ups and downs.The extra heavy oil boom began in early 2000's, when large projects started in Canada and Venezuela. But, rising plant cost, shortage of skilled workers, and environmental concerns have increased uncertainty of those projects, and finally this year global economic crunch and oil price plunge ended the boom. In those circumstances, technologies to reduce production cost are keenly craved and several are on trial in actual projects.In 2005, U.S. Congress directed the Bureau of Land Management to manage oil shale development on public lands. By 2008, the bureau issued six research development and demonstration leases that will allow oil shale development to resume on a 160-acre tract of public land. Currently, in-situ conversion process is arguably the most cost effective recovery method.The U.S. has led the world in coalbed methane (CBM) development, and the production reached 1.8 tcf by 2006. While some countries are after the footsteps of the U.S. in CBM development, the U.S. is now considering giving a higher priority to shale gas instead as the results of efforts to develop economical production methods for years.Japan has studied gas hydrate development since 1990's. In 2008, the Japan Oil, Gas and Metals National Corporation carried out a successful gas hydrate production test in Canada. The next step of their pursuit will include practical application of the production method, nationwide potential evaluation, and development of environmental assessment technique.

Uniformity of Distribution of Anhydrous Ammonia into Shelled Corn in a Continuous Ammoniator

Cost-effective recovery of non-fermentable, insoluble parts of the corn kernel before fermentation may increase the efficiency of fermentation and lower the overall cost of producing ethanol fuels. Treating whole corn with ammonia gas may weaken the physical structure of the kernel, and improve grinding and separations sufficiently to make fractionation of the non-fermentable components of the kernel cost-effective. The quick and even distribution of a controlled amount of ammonia into a batch of corn is problematic because the absorption of ammonia is rapid and exothermic. A device to continuously and evenly treat 2.3 kg/min (5 lb/min) of corn with ammonia gas (1000 mg N per kg corn) was designed, built, and tested. Ammonia was trapped and recycled within the treatment section of the ammoniator by feeding continuous streams of buffer solution and air flowing counter-current to the corn through the device. The kernel residence time in the treatment section was approximately 8 min. An assay for the ammonia content of individual corn kernels was developed, and the standard deviation among kernels from samples of ammoniated corn showed that ammonia was much more evenly distributed in the continuous ammoniator than in a bench-scale batch ammoniator.

Cost-Effective Recovery and Purification of Polyhydroxyalkanoates by Selective Dissolution of Cell Mass

Highly efficient separation and purification of polyhydroxyalkanoates (PHAs) from PHA-containing cell mass is essential to production of the bioplastics from renewable resources in a cost-effective, environmentally friendly way. Based on selective dissolution of non-PHA cell mass (NPCM) by protons in aqueous solution and crystallization kinetics of PHA biopolymers, a simple process is developed and demonstrated to recover PHAs from cell mass to high purity (>97 wt %) with high yield (>95 wt %). The average molecular weight of biopolyesters is controlled, which follows an exponential function of process severity, a combined factor of processing conditions. Compared with conventional chemical treatment such as sequential surfactant and hypochlorite treatment, this new technology substantially reduces the chemical cost for PHA recovery and purification from PHA-containing cell mass.