Application of δ-MnO2 and biochar materials in an arsenic-contaminated groundwater.

Two activated biochar materials, peanut char (δ-MnO2 /A-PC) and corn char (δ-MnO2 /A-CC), were used to treat an arsenic solution containing 97.5% As(III) and 2.5% As(V). After reacting with δ-MnO2 /A-PC for 24 h, 18.8% of As(III) and 35.4% of As(V) remained in the solution, revealing that some As(III) was oxidized to As(V) and the other was removed by adsorption. However, δ-MnO2 /A-CC caused the solution to retain 15.6% of As(III) and 41.7% of As(V) under the same conditions, indicating that δ-MnO2 /A-CC had higher oxidation for arsenic species than δ-MnO2 /A-CC. Adsorption capacities for δ-MnO2 /A-PC and δ-MnO2 /A-CC to arsenic were 1.50 and 1.53 mg/g in a solution with 0.5 ppm As(III), respectively. After coating with δ-MnO2 , the proportion of mesopore surface areas of δ-MnO2 /A-CC increased from 33.3% to 79.0%, but their mesopore volumes increased from 67.6% to 89.4%. Fourier-transform infrared spectroscopy and X-ray diffraction analyses demonstrated that δ-MnO2 was coated onto the surfaces of the biochars. The 600°C-ACC had a higher specific surface area, 221 m2 /g, than the δ-600°C-APC, 81.5 m2 /g; δ-MnO2 /A-CC could attach more Mn (38.2%) than δ-MnO2 /A-PC (27.8%). The elemental analysis revealed that δ-MnO2 /A-PC and δ-MnO2 /A-CC had similar carbon contents of 26.2%. PRACTITIONER POINTS: The δ-MnO2 /biochar adsorbent can oxidize As(III) into As(V) in the groundwater. δ-MnO2 /biochar adsorbed large amounts of As(III) and As(V). Adsorbent that contains more δ-MnO2 has a higher oxidation capacity. The δ-MnO2 /biochar made from corn stalks could combine with more δ-MnO2 .

Permeable reactive barrier of waste sludge from wine processing utilized to block a metallic mixture plume in a simulated aquifer.

Heavy metal contamination in underground water commonly occurs in industrial areas in Taiwan. Wine-processing waste sludge (WPWS) can adsorb and remove several toxic metals from aqueous solutions. In this study, WPWS particles were used to construct a permeable reactive barrier (PRB) for the remediation of a contaminant plume comprising HCrO4-, Cu2+, Zn2+, Ni2+, Cd2+, and AsO33- in a simulated aquifer. This PRB effectively prevented the dispersals of Cu2+, Zn2+, and HCrO4-, and their concentrations in the pore water behind the barrier declined below the control standard levels. However, the PRB failed to prevent the diffusion of Ni2+, Cd2+, and AsO33-, and their concentrations were occasionally higher than the control standard levels. However, 18% to 45% of As, 84% to 93% of Cd, and 16% to 77% of Ni were removed by the barrier. Ni ions showed less adsorption on the fine sand layer because of the layer's ineffectiveness in multiple competitive adsorptions. Therefore, the ions infiltrated the barrier at a high concentration, which increased the loading for the barrier blocking. The blocking efficiency was related to the degree of adsorption of heavy metals in the sand layer and the results of their competitive adsorption.

Removal of heavy metals from contaminated paddy soils using chemical reductants coupled with dissolved organic carbon solutions.

General acid washing is commonly used to treat heavy metal-contaminated soils, but it is sometimes difficult to achieve remediation aims in severely polluted soils. If we expose the surfaces of Fe oxide minerals to reductive dissolution during washing treatment, more of the metals initially adsorbed to these surfaces will be liberated, which may encourage the removal of heavy metals. Initially, the metal extraction capabilities of nine chemical reductants were compared in ten soil samples polluted by Cr, Cu, Zn, and Ni. Sodium dithionite (Na2S2O4) and ferrous sulfate (FeSO4) were screened for subsequent intensive research. In summary, the Na2S2O4 solutions had higher Cr, Cu, and Zn removal rates than either the FeSO4 or acid solution. Application of dissolved organic carbon (DOC) further increased the removal of heavy metals by complexation. About 15%, 86%, 32%, and 52% of the Cr, Cu, Zn, and Ni, respectively, were removed from the representative soil (M-2) by two-stage washing using 0.2 M Na2S2O4 coupled with 1,500 mg L-1 DOC solution at pH 2.0. Meanwhile, most soil fertility was preserved: ammonium nitrogen was increased 3.9 times; the increase in exchangeable potassium was 33%; and the reduction in available P was only 10%.

Wine-processing waste sludge permeable reaction barrier utilized to block a gasoline plume in a simulated aquifer.

Oil leakage from gas stations in Taiwan is commonly caused by the corrosion of oil tanks or loose pipeline joints, contaminating the soil and groundwater near the gas station. Wine-processing waste sludge (WPWS) does not contain toxic substances and has a high organic matter content. Thus, it has high affinity for methyl tert-butyl ether (MTBE) and benzene, toluene, ethylbenzene, and xylenes (BTEX), being suitable for application in preventing and controlling groundwater pollution. In this study, a permeable reaction barrier (PRB) constructed utilizing WPWS in a large water tank was designed to simulate the diffusion and blockage of gasoline plumes in an aquifer. The constructed WPWS PRB had a rectangular shape with a thickness and height of 9 and 60 cm, respectively. The depth in the aquifer was adjusted to 50 cm. MTBE was detected in the aquifer downstream of the WPWS PRB every day during the experiment; however, the maximum concentration detected was only 5.33 ppb. BTEX were only detected on 3 days during the experiment and had maximum concentrations of 1.76, 2.28, 0.34, and 0.60 ppb, which are below the water quality control standards.

Removal of methylene blue from aqueous solution using sediment obtained from a canal in an industrial park.

Drainage canal sediments in an industrial park are generally dredged to landfill in Taiwan. The objective of this study was to evaluate feasibility employing the sediment as an adsorbent for removal of dye. The sediment contained approximately 10% of organic matter and little heavy metals. Infrared (IR) analysis revealed that carboxyl was the most important functional group for methylene blue (MB) sorption. Canal sediment could remove the most MB from water at pH 8.0 and this removal increased with increasing temperature. The MB sorption was well described by the Langmuir, Dubinin-Radushkevich, and Temkin sorption isotherms at 10°C, but it showed good compliance with Freundlich isotherm at 25°C and 40°C. The MB adsorption was a spontaneous and endothermic reaction; its maximum calculated adsorption capacity (Qm) was 56.0 mg g-1 at 10°C by the Langmuir isotherm. The calculated values of enthalpy (ΔH°) and entropy (ΔS°) are 14.6 kJ mol-1 and 149.2 kJ mol-1, respectively. Only pseudo-second-order adsorption kinetic model successfully described the kinetics of MB onto the sediment at different operation parameters. Activation energy of MB adsorption calculated from Arrhenius equation was 16.434 kJ mol-1, indicating the binding between canal sediment and MB was a physical adsorption.

Reclamation of zinc-contaminated soil using a dissolved organic carbon solution prepared using liquid fertilizer from food-waste composting.

A liquid fertilizer obtained through food-waste composting can be used for the preparation of a dissolved organic carbon (DOC) solution. In this study, we used the DOC solutions for the remediation of a Zn-contaminated soil (with Zn concentrations up to 992 and 757 mg kg(-1) in topsoil and subsoil, respectively). We then determined the factors that affect Zn removal, such as pH, initial concentration of DOC solution, and washing frequency. Measurements using a Fourier Transform infrared spectrometer (FT-IR) revealed that carboxyl and amide were the major functional groups in the DOC solution obtained from the liquid fertilizer. Two soil washes using 1,500 mg L(-1) DOC solution with a of pH 2.0 at 25°C removed about 43% and 21% of the initial Zn from the topsoil and subsoil, respectively. Following this treatment, the pH of the soil declined from 5.4 to 4.1; organic matter content slightly increased from 6.2 to 6.5%; available ammonium (NH4(+)-N) content increased to 2.4 times the original level; and in the topsoil, the available phosphorus content and the exchangeable potassium content increased by 1.65 and 2.53 times their initial levels, respectively.

Kinetic and thermodynamic studies on removal of Cu(II) from aqueous solutions using soil nanoclays.

Soil clays (< 2,000 nm) (SC) and soil nanoclays (< 100 nm) (SNC) were used as adsorbents for removal of Cu(II) from aqueous solution. The experiments were conducted with variables including pH, interaction time, concentration of Cu(II) and temperature. Four kinetic models have been employed to investigate adsorption mechanisms, and the experimental data more closely resemble a second-order process of the kinetic model. Adsorption studies on soil nanoclays have been shown to be highly effective in removing of Cu(II) from aqueous solution. This adsorbent is widely available as a natural material, is mechanically stable and, most importantly, it is environmentally appealing. The maximum Cu(II) adsorption capacity of soil nanoclays (31.7 mg/g) is more than three times higher than natural soil clays (10.2 mg/g). Our study demonstrates that soil nanoclays can be used effectively for removal of Cu(II) from aqueous systems to achieve environmental cleaning purposes.

Reclamation of copper-contaminated soil using EDTA or citric acid coupled with dissolved organic matter solution extracted from distillery sludge.

Soil washing using a strong chelating agent is a common practice for restoring contaminated soils, but significant soil fertility degradation and high operation costs are the major disadvantages. Washing soil with a dissolved organic matter (DOM) solution has been identified as a method that can moderate the loss of nutrients in the soil and enhance metal removal. The DOM solutions were extracted from waste sludge obtained from a local whisky distillery. Single chelating washing and chelate-DOM washing were carried out using ethylenediaminetetraacetic acid (EDTA), citric acid, and DOM solutions to remediate highly Cu-contaminated soil. Two-phase washing using 0.34 M citric acid and then 1500 mg L(-1) DOM solution (pH 8.5) was found to be most favorable for the soil. With this treatment, 91% Cu was removed from the topsoil; the organic matter, cation exchange capacity, plant-available nitrogen, and available phosphate content increased by 28.1%, 103%, 17.7%, and 422%, respectively.

Reclamation of cadmium-contaminated soil using dissolved organic matter solution originating from wine-processing waste sludge.

Soil washing using an acid solution is a common practice for removing heavy metals from contaminated soil in Taiwan. However, serious loss of nutrients from soil is a major drawback of the washing. Distillery sludge can be used to prepare a dissolved organic matter (DOM) solution by extracting its organic constituents with alkaline solutions. This study employed DOM solutions to remediate Cd-contaminated soil (with concentrations up to 21.5 mg kg(-1)) and determine the factors affecting removal of Cd, such as pH, initial concentration of DOM solution, temperature, and washing frequency. When washing with pH 3.0 and 1250 mg L(-1) DOM solution, about 80% and 81% of Cd were removed from the topsoil at 27 °C and subsoil at 40 °C, respectively. To summarize the changes in fertility during DOM washing with various pH solutions: the increase in organic matter content ranged from 7.7% to 23.7%; cation exchange capacity (CEC) ranged from 4.6% to 13.9%; available ammonium (NNH(4)) content ranged from 39.4% to 2175%; and available phosphorus content ranged from 34.5% to 182%. Exchangeable K, Ca, and Mg remained in the topsoil after DOM washing, with concentrations of 1.1, 2.4, and 1.5 times higher than those treated with HCl solution at the same pH, respectively.

Adsorption of Cu(II) from aqueous solution by wine processing waste sludge.

Wine processing waste sludge (WPWS) has been shown to be an effective sorbent for sorption of nickel, lead, and chromium, but the sorption of copper (Cu) in aqueous solution by WPWS has not been conducted. The objective of this study was to explore the sorption mechanism of WPWS for copper. Infrared analysis revealed carboxyl was the major functional group in WPWS. The WPWS sorption isotherms of copper were only well described by Langmuir sorption isotherm. The maximum adsorption capacity (Qm) was 14.26 mg/g at 50 degrees C. A pseudo-second-order sorption kinetic model successfully described the kinetics of copper sorption onto WPWS. The Gibb free energies (deltaG0) ranged from -20.69 to -24.29 kJ mol(-1), and the deltaH0 and deltaS0 were 5.048 kJ mol(-1) and 91.05 J mol(-1) K(-1), respectively. The trend of the intra-particular diffusion rate is the opposite of the adsorption constant of the pseudo-second-order equation.

Removal of methylene blue from aqueous solution using wine-processing waste sludge.

Dye wastewaters usually contain toxins and high chroma, making them difficult to treat with biological methods. The adsorption process plays an important role in removing dyes from wastewaters. This study aimed to explore the methylene blue (MB) adsorption mechanism by wine-processing waste sludge (WPWS). The WPWS contains a high cation-exchange capacity (64.2 cmol(c) kg(-1)) and organic matter (52.8%). The parameters affecting MB adsorption included pH, initial concentration of MB, reaction temperature, particle size and dosage of WPWS. The WPWS adsorption isotherms of MB were only well described by Langmuir adsorption isotherm. The maximum adsorption capacity (Q(m)) of MB was 285.7 mg g(-1) at 25 °C. The activation energy determined by Arrhenius equation is 29.995 kJ mol(-1). Under steady-state reaction conditions, the Gibb free energy (ΔG°) ranged from -24.607 to -27.092 kJ mol(-1) and ΔH° was -8.926 kJ mol(-1), indicating that lower reaction temperature would favor MB adsorption. Therefore, MB adsorption by WPWS was a spontaneous, exothermic and physisorption reaction.

Effect of age on the incidence of acute hepatitis B after 25 years of a universal newborn hepatitis B immunization program in Taiwan.

BACKGROUND: Raising concerns about the waning immunity of cohorts receiving hepatitis B virus (HBV) vaccination in infancy persuaded us to identify the changing incidence of acute hepatitis B (AHB) in children and young adults. METHODS: Data on AHB surveillance through the National Notifiable Disease Surveillance System from July 2001 to June 2009 were collected and described. Cases were divided into 2 cohorts according to their birth year: before or after the universal newborn HBV vaccination program. Age-specific incidence was compared for the 2 birth cohorts with diagnosis at age 15-24 years. RESULTS: In total, 2226 patients with AHB were identified. AHB rates varied by age; the highest rates occurred among unvaccinated individuals aged 25-39 years (2.33/100 000). Due to breakthrough HBV infection from mother-to-infant transmission, vaccinated infants (0.78/100 000) had higher rates than those aged 1-14 years (0.04/100 000), who had the lowest rates. The incidence in vaccinated birth cohorts was significantly lower than in unvaccinated birth cohorts among patients 15-24 years old, with an adjusted-relative risk of 0.42. CONCLUSIONS: Implementation of universal-at-birth HBV immunization programs has effectively reduced the occurrence of AHB among adolescents and young adults in Taiwan for >25 years, making infants and the 25-39-year-old cohort additional targets for preventing AHB.

Aluminium and nutrients induce changes in the profiles of phenolic substances in tea plants (Camellia sinensis CV TTES, No. 12 (TTE)).

BACKGROUND: Tea plants are always cultivated in acid soils in hilly regions and their growth can be dependent on to soluble aluminium (Al). The mechanism of Al detoxification and the influence of Al on phenolic compounds (i.e. catechin) in the roots of tea plants has remained obscure. This study aimed to investigate the influence of Al changes on the concentrations of phenolic substances in tea plants through hydroponic experiments. RESULTS: Tea plants were cultivated in nutrient solution containing 1.5 and 2.5 mmol L(-1) Al, and these treatments enhanced the growth of new buds and roots. Aluminium stimulated the uptake of Ca, Mg, K and Mn, whereas the uptake of Fe, Cu and Zn was retarded. Moreover, total phenol concentrations in tea plant tissues increased with increasing Al concentrations. In general, catechin concentrations in leaves increased with increasing Al concentrations in the hydroponic experiments. High correlation coefficients were obtained between Al and (-)-ECG (r(2) = 0.85, P < 0.01) and between Al and total phenols (r(2) = 0.92, P < 0.01). CONCLUSIONS: The Al concentration in tea plants indeed increases catechin concentrations and plays an important role in the growth of tea plants.

Change in hepatitis A epidemiology after vaccinating high risk children in Taiwan, 1995-2008.

Taiwan started to immunize children in 30 indigenous townships against hepatitis A since June 1995. The program was further expanded to 19 non-indigenous townships with higher incidence or increased risk of epidemic in 1997-2002, covering 2% of total population. Annual incidence of hepatitis A decreased from 2.96 in 1995 (baseline period) to 0.90/100,000 in 2003-2008 (vaccination period). The incidence in vaccinated townships and unvaccinated townships declined 98.3% (49.66-0.86/100,000) and 52.6% (1.90-0.90/100,000). In 2003-2008, incidence doubled in people aged >=30 years, mostly in unvaccinated townships (0.42-0.92). During 2003-2008, travel to endemic countries was the most commonly reported risk factor (13.5%). First dose vaccine coverage was 78.8% in 1994-2005 birth cohort. Taiwan's experience demonstrates the great, long-term efficacy of hepatitis A vaccine in disease control in vaccinated townships, and out-of-cohort effect in unvaccinated townships. Further reduction can be achieved by improving vaccination coverage of adults at risk.

Application of bifunctional magnetic adsorbent to adsorb metal cations and anionic dyes in aqueous solution.

A magnetic adsorbent, amine-functionalized silica magnetite (NH(2)/SiO(2)/Fe(3)O(4)), has been synthesized to behave as an anionic or cationic adsorbent by adjusting the pH value of the aqueous solution to make amino groups protonic or neutral. NH(2)/SiO(2)/Fe(3)O(4) were used to adsorb copper ions (metal cation) and Reactive Black 5 (RB5, anionic dye) in an aqueous solution in a batch system, and the maximum adsorption were found to occur at pH 5.5 and 3.0, respectively. The adsorption equilibrium data were all fitted the Langmuir isotherm equation reasonably well, with a maximum adsorption capacity of 10.41 mg g(-1) for copper ions and of 217 m g g(-1) for RB5. A pseudo-second-order model also could best describe the adsorption kinetics, and the derived activation energy for copper ions and RB5 were 26.92 kJ mol(-1) and 12.06 kJ mol(-1), respectively. The optimum conditions to desorb cationic and anionic adsorbates from NH(2)/SiO(2)/Fe(3)O(4) were provided by a solution with 0.1M HNO(3) for copper ions and with 0.05 M NaOH for RB5.

The Fas-mediated apoptotic pathway in cardiac myxoma.

Cardiac myxoma is the most common primary tumor of the heart. The existence of apoptosis in cardiac myxoma has been demonstrated. The purpose of this investigation was to elucidate the pathway of apoptosis and the cell cycle in cardiac myxomas. This study had 2 parts: investigation of a cultured cardiac myxoma cell line and the analysis of data from 20 patients with cardiac myxoma that was surgically excised. Apoptosis signal transduction was determined by assessing DNA fragmentation, Fas ligand (FasL), Fas, tumor necrosis factor-α (TNF-α), caspase-3, and terminal deoxynucleotidyl transferase nick-end labeling (TUNEL) assay through immunohistochemical stain, quantitative reverse transcriptase- polymerase chain reaction (RT-PCR), and Western blot analysis. The patient population consisted of 12 (60%) women and 8 (40%) men with a mean age of 46 years (range = 32-64 years). All cases of myxoma were sporadic myxomas rather than familial. Clinical presentations included asymptomatic (26%), dyspnea (44%), stroke (9%), chest pain (9%), and fever (11%). All myxomas were located in the left atrium. Pathological scores for inflammation, cellularity, calcification, and thrombosis were not related to myxoma location or clinical events. In cardiac myxoma, apoptosis documented by TUNEL (70.9% ± 17.6%) and the caspase-3 (66.5% ± 32.5%) final common pathway is characterized by the extrinsic Fas/ FasL dependent pathway (positive stained 70.9% ± 19.2%; 26.0% ± 17.2%, respectively), but not the intrinsic pathway. The RT-PCR and Western Blot analysis (Fas/FasL, TNF-α, caspase-3, and apoptosis) of the cardiac myxoma and cultured cardiac myxoma cells confirmed the immunochemical results. The extrinsic Fas/FasL-dependent apoptosis pathways in cardiac myxomas were proved by both RNA and protein levels.

Polymerization of catechin catalyzed by Mn-, Fe- and Al-oxides.

The role of short-range order (SRO) metal oxides, which are common in acid soils and associated environments, in influencing the abiotic transformations of catechin, which is common in the soil of tea plantations, still remains poorly understood. The aim of this study was to investigate the catalytic power of SRO Mn(IV)-, Fe(III)- and Al-oxides in influencing the abiotic transformations of catechin. At the end of a 90-h reaction period, the release of CO(2) in all the oxide-catechin systems is higher than that for the system with only catechin. Polymerization of catechin is catalyzed and enhanced by SRO-oxides, as is indicated by the absorbance values of the supernatants, which were obtained via visible adsorption spectroscopy, and the yields of humic polymers. The sequence of the oxides that increased the yield of total humic polymers in these systems under ambient atmosphere is: Fe(III)-oxide>Mn(IV)-oxide>Al-oxide>>no catalyst (catechin). The electron spin resonance (ESR) and Fourier transformation infrared absorption spectrometry (FT-IR) of humic polymers formed in the oxide-catechin systems were similar to the spectra obtained from the humic polymers extracted from the soil. The catalytic power of SRO-oxides in promoting the oxidative polymerization of catechin, the resultant formation of humic substances, and C turnover in acid soils thus merit attention.

Biosorption of chromium, copper and zinc by wine-processing waste sludge: single and multi-component system study.

Wine-processing waste sludge (WPWS) has been shown to have powerful potential for sorption of some heavy metals (i.e., chromium, lead and nickel) in single-component aqueous solutions. But although most industrial wastewater contains two or more toxic metals, there are few sorption studies on multicomponent metals by WPWS. This study has two goals: (i) conduct competitive adsorption using Cr, Cu and Zn as sorbates and examine their interaction in binary or ternary systems; and (ii) determine the effects of temperature on the kinetic sorption reaction. The sludge tested contained a high amount of organic matter (38%) and had a high cation exchange capacity (CEC, 255 cmol(c)kg(-1)). Infrared analysis reveals that carboxyl is the main functional group in this WPWS. The (13)C NMR determination indicates alkyl-C and carboxyl-C are major organic functional groups. At steady state, there are about 40.4% (Cr), 35.0% (Cu) and 21.9% (Zn) sorbed in the initial 6.12 mM of single-component solutions. Only pseudo-second-order sorption kinetic model successfully describes the kinetics of sorption for all experimental metals. The rate constants, k(2), of Cr, Cu and Zn in single-component solutions are 0.016, 0.030 and 0.154 g mg(-1)min(-1), respectively. The sorption of metals by WPWS in this competitive system shows the trend: Cr>Cu>Zn. Ions of charge, hydrated radius and electronic configuration are main factors affecting sorption capacity. The least sorption for Zn in this competitive system can be attributed to its full orbital and largest hydrated radius. Though the effect of temperature on Zn sorption is insignificant, high temperature favors the other metallic sorptions, in particular for Cr. However, the Cr sorption is lower than Cu at 10 degrees C. The Cr sorption by WPWS can be higher than that of Cu at 30 degrees and 50 degrees C.