Ammonia oxidation by in-situ chloride electrolysis in etching wastewater of semiconductor manufacturing using RuSnOx/Ti electrode: Effect of plating mode and metal ratio.

The indirect chloride-mediated ammonia oxidation encounters challenges in maintaining the effectiveness of metal oxide anodes when treating wastewaters with complex compositions. This study aims to develop a highly stable anode with RuO2-SnO2 coatings for treating an etching effluent from semiconductor manufacturing, which majorly contains NH3 and organic compounds. The RuSnOx/Ti electrode was synthesized using wet impregnation and calcination processes. The metal oxide configuration on Ti plate substrate was tuned by varying the step-dipping process in RuCl3 and SnCl4 baths. A 10-day continuous-flow electrolysis was conducted for studying the ammonia removal and chlorine yield under variable conditions, including detention, pH, current density, and initial ammonia and chloride concentrations. In the RuSnOx coatings, the configuration comprising RuO2 nanorods as the surface layer and an intermediate layer of SnO2 crystallites (by plating Ru3+ for three times to cover one Sn4+ layer, denoted as the Ru3Sn/Ti electrode) exhibited the best durability for acid washing, along with relatively high Faradaic efficiency and low energy consumption. To further improve the treatability of real wastewater (NH3-N = 634 mg L-1, chemical oxygen demand (COD) = 6700 mg L-1, Cl- = 2000 mg L-1, pH 11), the duel-cell electrolyzers were constructed in series under a current density of 30 mA cm-2 and 45 min detention. Ultimately, removals of NH3 and COD reached 95.8% and 76.3%, respectively, with successful limitation of chloramine formation.

Optimizing Treatment for Combined Midshaft Clavicle Fracture and Acromioclavicular Joint Injury: A Case Study Highlighting the Efficacy of Knowles Pin Fixation.

BACKGROUND An ipsilateral fracture of the midshaft clavicle with dislocation of the acromioclavicular joint (ACJ) is a rare combination injury and almost always occurs following high-energy trauma. Currently, there is no optimal surgical approach for this kind of rare injury. We present a 60-year-old man with a traumatic combined linear midshaft clavicle fracture and ACJ injury simultaneously treated with Knowles pin fixation. CASE REPORT A 60-year-old male patient presented a linear midshaft clavicle fracture in the emergency room (ER) due to a road traffic accident. A linear fracture progressed to a displaced fracture at followup in the outpatient orthopedic department 3 days later. After open reduction with Knowles pin fixation for displaced clavicle fracture, postoperative followup radiographs revealed unexpected ipsilateral type V ACJ dislocation according to Rockwood classification. The next day, a closed reduction with percutaneous Knowles pin fixation was performed for ACJ dislocation. At the 1-year followup, radiographic and clinical results demonstrated complete union of the clavicle fracture and anatomic reduction of the ACJ with painless and full range of motion. CONCLUSIONS This report highlights that even a linear midshaft clavicle fracture can be combined with ipsilateral ACJ dislocation if the traumatic injury was caused by a high-energy road traffic accident. Therefore, an intraoperative stress view of the injured shoulder is recommended to recheck the stability of the ACJ after the clavicle fracture fixation to prevent a missed ACJ injury. In our case, an excellent outcome was achieved by using Knowles pin fixation simultaneously to treat the dual shoulder injury.

Heroin-induced osteoporosis presented with bilateral femoral neck insufficiency fractures in a male adult: a case report.

BACKGROUND: Osteoporosis has been associated with several disorders; however, there have been only a limited number of reports on heroin-induced osteoporosis. We report a rare case presented with bilateral femoral neck insufficiency fractures without trauma history, caused by heroin-induced osteoporosis. We collect sufficient clinical data and further shed light on the potential mechanism of how heroin affects bone formation and decreases bone density. CASE PRESENTATION: A 55-year-old male patient with normal body mass index (BMI) suffered from bilateral hips pain gradually without trauma history. He had intravenous heroin addiction for more than 30 years. Radiography revealed bilateral femoral neck insufficiency fractures. Laboratory tests showed elevated alkaline phosphatase levels (365 U/L) and decreased inorganic phosphate (1.7 mg/dL), calcium (8.3 mg/dL), 25-(OH)D3 (20.3 ng/ml) and testosterone levels (2.12 ng/ml). Magnetic resonance imaging (MRI) revealed increased signals on STIR images over the sacral ala and bilateral proximal femur, and multiple band-like lesions at the vertebrae of the thoracic and lumbar spine. Bone densitometry revealed osteoporosis with a T score of minus 4.0. The screen for urine morphine was positive (> 1000 ng/ml). Through assessment of the patient, the diagnosis was insufficiency fractures of bilateral femoral neck caused by opioid-induced osteoporosis. After hemiarthroplasty, regular medication with vitamin D3 and calcium, and detoxification treatment, and the patient recovered well after 6 months of follow-up. CONCLUSION: The aim of this report is to highlight the laboratory and radiology findings in a case of osteoporosis caused by opioid addiction and discuss the potential pathway by which osteoporosis is induced by opioids. When an unusual osteoporosis presents with insufficiency fractures, heroin-induced osteoporosis should be considered.

Clinical Application of the Peroneal Artery Perforator Flap for Reconstruction of Lateral Malleolus Defects.

The reconstruction of defects of the lateral malleolus involving the exposed fibular bone or tendon is challenging. This study aimed to evaluate the clinical application of the peroneal artery perforator flap with or without split-thickness skin grafting for soft tissue reconstruction of the bony defect of the lateral malleolus of the ankle joints. Reconstruction using a peroneal artery perforator flap with or without split-thickness skin grafting was performed for 15 patients (10 men, 5 women) between January 2007 and December 2018. The mean age was 53.7 years, and the mean size of the flaps was 40 cm2. The flaps were elevated in the form of a perforator flap, and split-thickness skin grafting was performed over the flaps and adjoining raw areas. The flaps survived in all cases; however, partial necrosis was observed in 3 cases. In cases of small-sized defects of the lateral malleolus of the ankle joints where a flap is required for the exposed bone or tendon, reconstruction using the peroneal artery perforator flap is advantageous, since the morbidity rate of the donor site is low and soft tissue is reconstructed.

Photo-persulfate oxidation and mineralization of benzoic acid: Kinetics and optimization under UVC irradiation.

The strong oxidant, persulfate (PS, S2O82-), was applied to treat the synthetic wastewater of benzoic acid (BA) under UV irradiation. UVC light initiated a chain reaction that derived the sulfate radical (SO4•-) and hydroxyl radical (HO•) from S2O82- ion. The experiment parameters, including light irradiation (UVA and UVC), pH, dose ratio ([PS]0/[BA]0), initial concentration ([BA]0, mg/L), was optimized based on degradation efficiency and total organic carbon (TOC) removal of BA, which reached up to 100% and 96%, respectively, under pH 3.0. The best dose ratio was close to equivalent stoichiometry (and [PS]0/[BA]0 = 15) for the treatment of 100 mg-BA/L, suggesting that UV/S2O82- was able to completely convert BA to carbon dioxide and water. The scavenging test showed that SO4•- contributed to about 60% of degradation rate, which the HO• predominated the mineralization rate, i.e., TOC removal. A consecutive kinetic model was proposed to clarify the reaction sequence and rate-determining factor of photo-persulfate oxidation for benzoic acid.

The Utility of Indocyanine Green Dye Fluorescence Lymphography and Angiography During Wide Excision of Cutaneous Melanoma.

Background and Objectives. Lymph node status is the most important prognostic factor in cutaneous melanoma patients. Recent studies showed that indocyanine green (ICG) fluorescence lymphography helps locating sentinel nodes better. Sometimes, flap reconstruction is needed after wide excision of tumor. Indocyanine green fluorescence also simplifies the intraoperative design of flaps. This study investigates the use of ICG fluorescence in patients with cutaneous melanoma during operation. Methods. We performed a single-center, retrospective study of subjects with cutaneous melanoma using ICG lymphograhy and/or angiography during wide excision of tumor between 2015 and 2019. Patients received a dermal injection of ICG and patent blue (PB) dye. The positive node was excised. Indocyanine green angiography was utilized to visualize better skin paddle during flap reconstruction if needed. Results. A total of 37 sentinel lymph nodes (SLNs) were removed in 12 patients. Indocyanine green successful localization was found in 10 of the 12 patients (83%). Three patients were found with 6 metastatic nodes on final pathology. 100% of these 6 nodes were identified by ICG, while 83% (5/6) were positive PB. Three of the 12 patients received flap reconstruction after operation, and no major complications occurred. Conclusions. ICG dye lymphangiography is a good alternative for locating SLNs in patients with melanoma. It could also visualize well perfusion skin paddle during reconstruction. We reported a reproducible and simple method to utilize ICG fluorescence in cutaneous melanoma patients.

Catalytic oxidation and deionization of nitrite and nitrate ions using mesoporous carbon-supported nano-flaky cobalt and nickel oxyhydroxides.

The composite electrode of NiCo oxide supported by porous carbon was synthesized for nitrite oxidation and nitrate electro-sorption. The crystal structure and chemical state of the Co and Ni oxyhydroxides which were precipitated on loofah-derived activated carbon (AC) using hypochlorite were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), and BET surface area. The voltammetry showed that the redox couple of Co(II)/Co(III) and Ni(II)/Ni(III) as the mediator catalytically transferred the electrons of NO2-/NO3-; the Ni site had a relatively high transfer coefficient and diffusive current, while the Co site was better in the capacitive removal of the nitrite and nitrate compounds. A batch electrolysis of nitrite ions was operated under constant anodic potential mode (0 to + 1.5 V vs. Ag/AgCl) to assess the performance of the composite electrodes. The adsorption capacity of NiCo/AC (Ni = 5% and Co = 5% on AC by weight) was 23.5 mg-N g-1, which was twice that of AC substrate (7.5 mg-N g-1), based on a multilayer adsorption model. The steady-state kinetics of the consecutive reaction were derived to determine the rate steps of the electrochemical oxidation of NO2- and adsorption of NO3-.

Analysis of the Necrosis-Inducing Components of the Venom of Naja atra and Assessment of the Neutralization Ability of Freeze-Dried Antivenom.

Patients bitten by Naja atra who are treated with bivalent freeze-dried neurotoxic antivenom in Taiwan have an improved survival rate but develop necrotic wound changes. The World Health Organization (WHO) has suggested using the minimum necrotizing dose (MND) of venom as a method of evaluating the neutralization effect of antivenom. The aim of this study was to evaluate the effectiveness of antivenom for the prevention of necrosis based on the MND and clarify which component of the venom of N. atra induces necrosis. The neurotoxins (NTXs) were removed from the crude venom (deNTXs), and different concentrations of deNTXs were injected intradermally into the dorsal skin of mice. After three days, the necrotic lesion diameter was found to be approximately 5 mm, and the MND was calculated. A reduction in the necrotic diameter of 50% was used to identify the MND50. Furthermore, both phospholipase A2 (PLA2) and cytotoxins (CTXs) were separately removed from the deNTXs to identify the major necrosis-inducing factor, and the necrotic lesions were scored. All mice injected with deNTXs survived for three days and developed necrotic wounds. The MND of the deNTXs for mice was 0.494 ± 0.029 µg/g, that of the deNTXs-dePLA2 (major component retained: CTXs) was 0.294 ± 0.05 µg/g, and that of the deNTX-deCTX (major component retained: PLA2) venom was greater than 1.25 µg/g. These values show that CTX is the major factor inducing necrosis. These results suggest that the use of the deNTXs is necessary to enable the mice to survive long enough to develop venom-induced cytolytic effects. CTXs play a major role in N. atra-related necrosis. However, the MND50 could not be identified in this study, which meant that the antivenom did not neutralize venom-induced necrosis.

Adsorptive removal of dye in wastewater by metal ferrite-enabled graphene oxide nanocomposites.

Dyes are hazardous compounds commonly found in industrial wastewaters. Efficient and inexpensive removal of dye molecules from the water matrix has been demonstrated by adsorption processes. Magnetic nano-adsorbents, such as metal ferrites, can be efficiently recovered from the reaction mixture after treating the pollutant. Herein, MFe2O4@GO (M = Cu, Co or Ni) was synthesized via solution combustion method for the removal of dye molecules from aqueous solutions. The characteristics of the MFe2O4@GO, including surface area and pore diameter, surface functional groups, and elemental composition, were examined. Methylene blue was used as representative dye pollutant. Batch adsorption results conformed to the Langmuir isotherm. Maximum adsorption capacities of the MFe2O4@GO (M = Cu, Co or Ni) were 25.81, 50.15 and 76.34 mg g-1, respectively. Kinetics of methylene blue adsorption fitted the pseudo-second-order model. Overall, NiFe2O4@GO exhibited the highest adsorbent performance among the graphene-metal ferrites investigated, primarily because of its high specific surface area and presence of mesopores.

Nickel ferrite nanoenabled graphene oxide (NiFe2O4@GO) as photoactive nanocomposites for water treatment.

Nanocomposite materials can enhance the capabilities of water treatment processes such as photocatalysis. In this work, novel light-driven nanocatalysts were synthesized by using nickel ferrite (NiFe2O4) to nanoenable graphene oxide (GO) substrates. GO is an emerging 2D nanomaterial with high conductivity and adsorption properties. Moreover, the electric properties of GO improve photocatalytic performance by promoting charge carrier separation. Results of the characterization of the nickel ferrite nanoenabled graphene oxide (NiFe2O4@GO) nanocomposites demonstrate that homogeneous and stable photocatalysts were produced. The as-synthesized nanocatalysts enabled complete decolorization of the colored water matrix in short irradiation times of 150 min using minimal catalyst loading at 0.5 g L-1. The selective hook and destroy mechanism reduced the competitive effect of co-existing ions in solution. Furthermore, the use of specific scavengers helped to elucidate the degradation mechanisms of organic dye methylene blue by NiFe2O4@GO nanocomposites.

Recycling dredged harbor sediment to construction materials by sintering with steel slag and waste glass: Characteristics, alkali-silica reactivity and metals stability.

This work recovered the dredged sediment around Kaohsiung Harbor, Taiwan, for preparing lightweight aggregates (LWA), of which physicochemical properties as affected by the addition of basic-oxygen-furnace (BOF) slag and waste glass were investigated. LWA properties included water absorption, particle density, compressive strength, shrinkage, and microstructure of sintered pellets were evaluated to ensure feasibility of dredged harbor sediment reutilization technique. Results showed that adding appropriate amount of glass powders (~7%) to the mixtures of sediment and slag significantly reduced the water absorption (as low as 2.2%) of the sintered pellets and increase the compressive strength (as high as 23.1 MPa) of LWA, which were found to be controlled by open porosity and shrinkage. Excessive addition of glass (>10%) led to increase in internal pore sizes of the sintered pellets, and thus reduced the compressive strength. The alkali-silica reactivity (ASR) of the LWA was innocuous according to the ASTM C289 test. Sintering and glass addition improved the stability of heavy metal and environmental compatibility of the LWA. The recycling of waste sediment, slag, and glass for LWA production can provide an alternative for the disposal of dredge harbor sediment and has positive impact on waste reduction, which not only can reduce secondary contamination to the environment, but also can contribute to circular economy.

Detecting phthalate esters in sludge particulates from wastewater treatment plants.

This study proposed a method for analysis of 10 phthalate esters compounds from wastewater treatment plant sludges. The analytical efficiency of GC-MS for of target compounds was verified by a standard mixture of phthalate esters. The response factors related to the respective internal standards from a five-point calibration curve quantified the phthalate esters in individual compounds. Based on the literature compiled by environmental agencies, new generation phthalate compounds have been developed, such as di-iso-nonyl phthalate (DiNP), di-iso-decyl phthalate (DiDP), as alternative to conventional phthalates. The analytical results showed that the total PAEs concentration was in the range from 7.4 to 138.6 mg kg-1 dw in these seven analyzed sludge samples. More, di-iso-nonyl phthalate (DiNP), di-iso-decyl phthalate (DiDP) and bis(2-ethylhexyl) phthalate (DEHP) contributed to over 99% of PAEs in the sludge. The correlation between total PAEs concentration in household and sewage flow treated at seven WWTPs and concentrations of DEHP, DiNP and DiDP was significant.

Nonionic and anionic surfactant-washing of polycyclic aromatic hydrocarbons in estuarine sediments around an industrial harbor in southern Taiwan.

Various surfactants, such as nonionic Triton X-100 and Simple Green™ (SG), and anionic sodium dodecylsulfate (SDS) and sodium dodecylbenzene sulfonate (SDBS) were utilized to remove polycyclic aromatic hydrocarbons (PAHs) from heavily contaminated harbor sediments dredged from Kaohsiung Harbor in Taiwan. Desorption/re-sorption equilibrium, kinetics, and washability of PAHs using the selected surfactant were evaluated under different critical micelle concentrations (CMC). Experimental results revealed that the desorption rate of high molecular weight PAHs was greater than those of low molecular weight PAHs, and the anionic SDS was relatively effective in the removal of total PAHs (>50%) compared to the other surfactants. The correlation between the effectiveness of the surfactant washing processes and the physicochemical properties of individual PAH was statistically analyzed. The resulting data suggested that hydrophobic factors (Kow, Koc and Sw) affected PAH treatability more than the reactivity of PAH (electron affinity and ionization potential). Since the adsorption of anionic surfactant altered the hydrophobicity of organic matter in the sediment, PAHs preferred transferring from the sediment to the hydrophobic core of micelles in aqueous solution. Nevertheless, the nonionic surfactant enhanced the PAH partition in the aqueous phase, thus increasing the micellar solubilization of PAH.

Loofah-derived activated carbon supported on nickel foam (AC/Ni) electrodes for the electro-sorption of ammonium ion from aqueous solutions.

Activated carbon (AC), prepared from dried loofah sponge, was supported on nickel foam to fabricate AC/Ni electrodes. The characteristics of ammonium electrosorption on AC/Ni electrodes was studied. Results showed that AC prepared in one-step activation (without pre-pyrolysis), i.e., OAC, had relatively low crystallinity, high mesoporosity, and high specific capacitance compared to those made in two-step carbonation followed by activation. Adsorption and desorption density of NH4+ were measured at constant potential of -1.0 V (vs. Hg/HgO) and +0.1 V (vs. Hg/HgO), respectively. Non-faradaic charging contributed to the electrochemical storage and adsorption of ammonium ions on the AC surface with a maximal charge efficiency of 80%, at an applied potential of -1.0 V (vs. Hg/HgO). Multiple-layer adsorption isotherm better described the electrosorption of ammonium ion on OAC/Ni electrodes yielding a maximum adsorption capacity of 6 mg-N g-1, which was comparable with other similar systems. Overall, results clearly demonstrated the effect of synthesis strategy on the capacitive charging behaviors of AC/Ni electrodes and its relationship to NH4+ electrosorption.

Electrochemical degradation of oxalic acid over highly reactive nano-textured γ- and α-MnO2/carbon electrode fabricated by KMnO4 reduction on loofah sponge-derived active carbon.

Manganese dioxide incorporated activated carbon (MnO2/AC) was synthesized and used to electrochemically degrade oxalic acid in aqueous solutions. The highly porous carbon provided reactive sites for the electro-sorption of oxalic acid and MnO2, with a specific polymorphism efficiently mediating the electron transfer between the electrode and organic pollutants. The activated carbon, made from the pyrolysis of dry loofah sponge using ZnCl2 as activating agent, exhibited a high double-layer capacitance dependent upon the heating temperature (100 F/g at 800 °C). The γ-MnO2 was in-situ deposited over the microporous structure of activated carbon through the redox reaction between KMnO4 and carbon. Simple further calcination converted γ-MnO2 to α-MnO2 nano-whisker at temperatures above 500 °C. Cyclic voltammetry showed that oxalic acid significantly improved the anodic current of the Mn(III)/Mn(IV) redox couple on the MnO2/AC electrode at an electrode potential around + 0.6 V (vs. Ag/AgCl). About 95% of oxalic acid degradation was achieved at pH < 4; meanwhile, 80% of the mineralization (total organic carbon removal) was attained independent of pH. Calcination converted γ-MnO2 to α-MnO2 which had higher electrochemical stability and inhibited the dissolution of Mn(II) from the electrode.

Electro-sorption of ammonium ion onto nickel foam supported highly microporous activated carbon prepared from agricultural residues (dried Luffa cylindrica).

An electrode made of loofah sponge derived activated carbon supported on nickel foam (AC/Ni) was successfully fabricated and used to remove ammonium ion (NH4+) from aqueous solution. A multilayer adsorption isotherm was used to describe ammonium electro-sorption on AC/Ni electrodes at different temperature, initial NH4+ concentration, and electrical field. The cyclic voltammetry (CV) results suggested that the electrical capacitance of AC/Ni electrodes, with the AC being prepared without preheating (OAC) or with low temperature heating (i.e., 300 AC), were higher than those prepared at high preheating temperature (i.e., 400 AC and 500 AC). Increasing the electro-sorption temperature from 10 to 50 °C decreased the monolayer NH4+ adsorption capacity from 5 to ca. 2-3 mg-N g-1, respectively. Background electrolyte, namely, sodium sulfate, exhibited significant competitive effect on the adsorption of ammonium ion at sodium ion concentration > 10-2 M. The activation energy and heat of adsorption were 9-23.2 kJ mol-1 and -3.7--10.7 kJ mol-1, respectively, indicating a physisorption and exothermic adsorption characteristics. Based on the kinetics and thermodynamics analysis, there was slight increase in the activation energy with elevating preheating temperature, which increased the quantity of micro-pores and surface heterogeneity of the AC materials. Overall, results clearly demonstrated that carbon pyrolysis played a role on the capacitive charging behaviors of electrodes and the efficiency of NH4+ electro-sorption on the AC/Ni electrodes.

Electrocoagulation of tetrafluoroborate (BF4-) and the derived boron and fluorine using aluminum electrodes.

Tetrafluoroborate anion (BF4-) is found in the streams of flue-gas desulfurization and borosilicate glasses etching which deteriorates water quality through slow hydrolysis into boric acid and fluoride. Decomposition and electrocoagulation (EC) of BF4- were studied using metallic aluminum as the sacrificial electrode. The dissolved Al(III) from the anode could efficiently decompose BF4- in forms of fluoroaluminate complexes, and the derived boric acid and fluoride ion were removed by sweep flocculation. Major variables were investigated to optimize EC, including the reaction pH, initial concentration of BF4-, current density and electrolyte type. The mechanism of EC process was elucidated with the kinetics of consecutive reactions. Experimental results suggested that the removal of BF4- and total fluoride were less influenced by pH, and that of total boron reached a maximum at pH 8 which favored the surface complexation between borate species and EC precipitates. Under the conditions: [BF4-]0 = 9.3 mM, [NaCl] = 10 mM, pH = 8.0, current density = 5 mA/cm2, 98.3% of BF4- was decomposed and the removal of total fluoride and boron attained 98.2% and 74.1%, respectively within 3 h. EC using the Al electrode outperformed the conventional chemical coagulation and reduced the levels of BF4, B(OH)3 and F- in aqueous solution synergically.

Modification of the Pedicled Anterolateral Thigh Myocutaneous Flap for the Reconstruction of Ischial Pressure Ulcers: A Retrospective Case Study of 21 Patients.

INTRODUCTION: Ischial pressure ulcers are considered the most difficult type of pressure ulcers (PUs) to treat. OBJECTIVE: The authors report the use of a pedicled anterolateral thigh (pALT) myocutaneous flap as an alternative for covering an ischial PU. MATERIALS AND METHODS: The authors retrospectively collected the data of 21 patients with an indurated recurrent ischial ulcer or a fresh ischial ulcer. A pALT myocutaneous flap was harvested without intramuscular dissection and skeletonization of the perforators for the ischial defect reconstruction. Two modified flap-insetting techniques, an open-route method and a subcutaneous tunnel method, were used for the ischial defect reconstruction. The open-route flap-insetting was used for a recurrent ulcer status after other surgical procedures, and the subcutaneous tunnel method was used for fresh ulcers. RESULTS: The mean follow-up period was 10 months (range, 4-14 months). During the postoperative follow-up, all open-route reconstructions resulted in flap take; however, poor healing with seroma was noted in 2 patients who had undergone pALT reconstruction with subcutaneous tunneling after other previous surgical reconstructions. CONCLUSIONS: In the authors' experience, because of constant blood supply, sufficient bulk, easy elevation, longer pedicle for the arc of rotation, primary closure of the donor site without morbidity, and a non-weightbearing flap donor site, the pALT myocutaneous flap for ischial ulcer reconstruction can serve as a primary treatment and secondary salvage.

Characteristics of trichloroethene (TCE) dechlorination in seawater over a granulated zero-valent iron.

The accumulation of halogenated organic contaminants in estuaries near harbor areas has been receiving increasing attention. This work demonstrates the reductive treatment of trichloroethene (TCE) within seawater and freshwater using a polymeric surfactant (polyvinyl alcohol-co-vinyl acetate-coitaconic acid) modified nanoscale zero-valent iron (GnZVI). Experimental parameters included the ratio of seawater to freshwater, reaction pH, dosage of GnZVI and initial TCE concentration. It was found that the rate of TCE reduction decreased with increasing weight ratio of seawater to freshwater (ka = 0.075 min-1 in freshwater and 0.01 min-1 in seawater); however, the rate substantially improved by increasing the dosage of GnZVI. A consecutive reaction model of adsorption/desorption and reductive dechlorination was established to assess the chemical kinetics of TCE and the intermediates over the GnZVI. The experimental results suggested that both the amount of free sites on the reductant and reactivity of iron to TCE dominated the degradation efficiency. Desorption was a rate-limiting step for the intermediates that evolved (DCE, VC and ethene) in the bulk solution. Under conditions: GnZVI = 5 g/L, reaction pH around 8 and initial TCE = 10 mg/L, the removal efficiency attained 95%, while the decline in the removal rate of TCE from the seawater could be simply improved by increasing GnZVI dosage (10 g/L). As a role of electron donor for water and TCE, ZVI might passivate with contact time, leading to formation of the main crystalline phase magnetite (Fe3O4) by the coprecipitation of oxidized iron (Fe(II)/Fe(III)) over the surfaces of ZVI particles.

Highly efficient recovery of ruthenium from integrated circuit (IC) manufacturing wastewater by Al reduction and cementation.

Ruthenium (Ru) is a rare-earth metal, which is employed widely in metal-processing industries. This study recovered Ru from the wastewater of an IC foundry by cementation using metallic aluminum (Al) powder as the sacrificial agent. Ru ions were efficiently reduced to the metal and coagulated with the derived aluminum hydroxide flocs. Experimental parameters included the particle size of Al, molar ratio of Al to Ru, initial Ru concentration and operation temperature. The recovery rate reached 99% under these conditions: particle size Al powder = 88-128 µm, Al/Ru molar ratio = 2.0, initial Ru = 200 mg L-1, temperature = 338.16 K, reaction time = 120 min, stirring speed = 150 rpm. The cemented Ru over Al powder was spherical with a rough surface. Kinetic modelling suggested that the diffusion of Ru through the ash layer of Al powder controlled the reaction rate with an activation energy of 40.75 kJ mol-1. A brief cost analysis demonstrated that the cementation of Ru yielded a profit of $0.180 per 0.1 m3-wastewater.