N-diacetic Acid Research Articles

Effect of soil washing with biodegradable chelators on the toxicity of residual metals and soil biological properties

Soil washing with chelators is a promising and efficient method of remediating metals-contaminated soils. However, the toxicity of residual metals and the effects on soil microbial properties have remained largely unknown after washing. In this study, we employed four biodegradable chelators for removal of metals from contaminated soils: iminodisuccinic acid (ISA), glutamate-N,N-diacetic acid (GLDA), glucomonocarbonic acid (GCA), and polyaspartic acid (PASP). The maximum removal efficiencies for Cd, Pb, and Zn of 85, 55, and 64% and 45, 53, and 32% were achieved from farmland soil and mine soil using biodegradable chelators, respectively. It was found that the capacity of ISA and GLDA to reduce the labile fraction of Cd, Pb, and Zn was similar to that of the conventional non-biodegradable chelator ethylenediaminetetraacetic acid (EDTA). The leachability, mobility, and bioaccessibility of residual metals after washing decreased notably in comparison to the original soils, thus mitigating the estimated environmental and human health risks. Soil β-glucosidase activity, urease activity, acid phosphatase activity, microbial biomass nitrogen, and microbial biomass phosphorus decreased in the treated soils. However, compared with EDTA treatment, soil enzyme activities distinctly increased by 5–94% and overall microbial biomass slightly improved in the remediated soils, which would facilitate reuse of the washed soils. Based on soil toxicity tests that employed wheat seed germination as the endpoint of assessment, the washed soils exhibited only slight effects especially after ISA and GLDA treatments, following high-efficiency metal removal. Hence, ISA and GLDA appear to possess the greatest potential to rehabilitate polluted soils with limited toxicity remaining.

A small heterobifunctional ligand provides stable and water dispersible core-shell CdSe/ZnS quantum dots (QDs).

We describe a simple method to prepare water dispersible core-shell CdSe/ZnS quantum dots (QDs) 1 by capping QDs with a new thiol-containing heterobifunctional dicarboxylic ligand 4 (DHLA-EDADA). This ligand, obtained on a gram scale through a few synthetic steps, provides a compact layer on the QDs, whose hydrodynamic size in H2O is 15 nm ± 3 nm. The colloidal stability is dramatically enhanced with respect to the well-known (±) α-lipoic acid (DHLA). The ligand affinity towards QDs and the water dispersibility of nanocrystals 1 are addressed by the dithiol groups of DHLA, which chelate the zinc of the shell, and by the dicarboxylic groups of the ethylenediamine-N,N-diacetic acid (EDADA) residue, respectively. The effects of pH, buffer solutions, and biological medium on the stability of QDs 1 were assessed by monitoring the photoluminescence (PL) and hydrodynamic size over time. Highly fluorescent QD dispersions, stable over extended periods of time and over broad pH ranges and buffer types, were obtained. Furthermore, we show that the DHLA-EDADA ligand 4 also endows QDs with functional groups suitable for further conjugation and for metal ion detection. As a case study to illustrate the potential of our approach, we report the preparation and characterization of a highly luminescent orange light emitting polymer-QD 1 composite film.

68Ga]PSMA-HBED-CC Uptake in Osteolytic, Osteoblastic, and Bone Marrow Metastases of Prostate Cancer Patients.

The aim of this study was to evaluate potential differences in "Glu-NH-CO-NH-Lys" radio-labeled with [68Ga]gallium N,N-bis[2-hydroxy-5-(carboxyethyl)benzyl]ethylenediamine-N,N-diacetic acid ([68Ga]PSMA-HBED-CC) uptake in osteolytic, osteoblastic, mixed, and bone marrow metastases in prostate cancer (PC) patients. This retrospective study was approved by the local ethics committee. Patients who received [68Ga]PSMA-HBED-CC positron emission tomography/computed tomography ([68Ga]PSMA-PET/CT) with at least one positive bone metastasis were included in this study. Only patients who have not received systemic therapy for their PC were included. Bone metastases had to be confirmed by at least one other imaging modality or follow-up investigation. The maximum standardized uptake value (SUVmax) and mean Hounsfield units (HUmean) of each metastasis were measured. Based on CT, each metastasis was classified as osteolytic (OL), osteoblastic (OB), bone marrow (BM), or mixed (M). One hundred fifty-four bone metastases in 30 patients were evaluated. Eighty out of 154 (51.9%) metastases were classified as OB, 21/154 (13.6%) as OL, 23/154 (14.9%) as M, and 30/154 (19.5%) as BM. The SUVmax for the different types of metastases were 10.6±7.07 (OB), 24.0±19.3 (OL), 16.0±21.0 (M), and 14.7±9.9 (BM). The SUVmax of OB vs. OL and OB vs. BM metastases differed significantly (p≤0.025). A significant negative correlation between HUmean and SUVmax (r=-0.23, p<0.05) was measured. [68Ga]PSMA-HBED-CC uptake is higher in osteolytic and bone marrow metastases compared to osteoblastic metastases. Information derived from [68Ga]PSMA-PET and CT complement each other for the reliable diagnosis of the different types of bone metastases in PC patients.

Corrosion Rates of Cr- and Ni-Based Alloys With Organic Acids and Chelating Agents Used in Stimulation of Deep Wells

SummaryAcid treatments of deep wells completed by use of chromium (Cr) -based tubulars represent a real challenge to the oil industry. On one hand, Cr-based tubulars are used to protect against carbon dioxide (CO2) corrosion, but on the other hand, the protective layer [chromium(III) oxide (Cr2O3)] dissolves in hydrochloric acid (HCl). This makes protection of Cr tubulars during acidizing very challenging, especially at high temperatures. At temperatures greater than 200°F, there is a need to add corrosion-inhibitor intensifiers, most of which depend on heavy metals [copper (Cu) or antimony (Sb)] or are not effective at temperatures greater than 300°F [e.g., potassium iodide (KI)].Over the last decade, a new chelant was developed, glutamic acid N, N-diacetic acid (GLDA), which can dissolve carbonate minerals from both carbonate and sandstone formations. This chelant can form wormholes in carbonates (both calcite and dolomite) and does not destabilize clay particles present in sandstone formations. In the present paper, the corrosion rate of GLDA solutions is compared with that of other chelants and simple organic acids that are used for carbonate dissolution, such as hydroxyethylethylenediaminetriacetic acid (HEDTA), acetic acid, and formic acid. All corrosion tests were conducted at high temperatures and pressures and extended for up to 6 hours at temperature and pressure. The Cr and nickel (Ni) -based coupons representing tubular metallurgy were examined thoroughly after the tests, and the spent fluids were analyzed for key cations [Cr, Ni, molybdenum (Mo), iron (Fe), and manganese (Mn)].Compared with formic acid, acetic acid, and even HEDTA, GLDA is much less corrosive to Cr-13 alloys. The results of this work show that GLDA at 20 wt% causes almost no corrosion with Cr-13 up to 300°F. Unlike GLDA, HEDTA was found to be corrosive at a pH = 3.8, and requires attention when used in wells completed with Cr-13-based tubulars. On more-corrosion-resistant Cr- or Cr-Ni-based alloys, such as super Cr-13, Duplex-2205, Inconel-625, and Incoloy-925, the corrosion rate of GLDA is still far below the acceptable limit of 0.02 to 0.05 lbm/ft2 up to 350°F. In wells with corrosive sweet and sour gases, tubulars consisting of low-carbon steel, Cr-based steel, or corrosion-resistant Cr-Ni alloys can be effectively protected by a combination of GLDA with a minimal amount of a suitable corrosion inhibitor. Because of its favorable environmental profile, this mixture meets all the Oslo-Paris Convention for the Protection of the Marine Environment of the Northeast Atlantic (OSPAR) requirements for use in the North Sea. On the basis of these results, GLDA solutions can be used to stimulate carbonate and sandstone wells completed with Cr- and Ni-based tubulars, while maintaining the integrity of the tubulars.

Structural characterization, ROS-inductive and proteasome inhibitory properties of ternary and binary copper(II) complexes of N2- and N2O2-ligands

The four copper(II) complexes involving ethylenediamine-N,N-diacetic acid (H2edda) and ethylenediamine (en), viz. [Cu(edda)(en)]H2O 1, [Cu(en)Cl2] 2, [Cu(edda)] 3 and [Cu2(Hedda)2Cl2] 4, were synthesized and characterized by various physical means. The crystal structures of 1 and 4 established them as mononuclear and dichlorido-bridged dicopper(II) complexes respectively. Complexes 1 and 4 showed weak and strong antiferromagnetic Cu…Cu interaction. Dynamic light scattering data of 3 suggested it to be a 3-dimensional coordination polymer in aqueous solution, gel and solid forms. The copper(II) species of 1–4 in aqueous solution were analysed by UV–visible and molar conductivity data. The weak hydroxyl radical-inducing property of free copper(II) ions in solution was enhanced by the chelation of both types of ligands. However, chelation of each or both of these ligands reduce the strong proteasome inhibitory property of the copper(II). All complexes inhibited the three proteolytic sites of the 20S proteasome, with the Trypsin-like site been mostly selectively inhibited.

Optical and electrical properties of purpurin and alizarin complexone as sensitizers for dye-sensitized solar cells

The optical and electrical properties of two dyes purpurin (1,2,4-trihydroxy-9, 10-anthracenedione) and alizarin complexone (alizarin-3-methylimino-N,N-diacetic acid) as sensitizers for dye-sensitized solar cells were investigated by using UV–Vis spectrum, FT-IR spectrum, cyclic voltammetry and I–V (current–voltage) characteristics. In addition, electrochemical impedance spectroscopy was adopted to research the electrons transfer process between each interface of the dye-sensitized solar cell. For comparison with the experiments, the frontier molecular orbitals, vibration analysis, the total static first hyperpolarizability and driving force of electron injection were calculated by using density functional theory (DFT) with B3LYP, at 6-31G(d) basis set. Moreover, the transition properties were investigated by using time-dependent density functional theory (TD-DFT) with PBEPBE functional at 6-311+G(d,p) basis set in theory. The solvent effect and basis set effect were taken into consideration to investigate the excited state properties of the dyes. The results showed that alizarin complexone had a higher energy conversion efficiency of 0.27 % than that of purpurin (0.13 %), with higher open circuit voltage ( $$V_{oc}$$ ) of 0.45 V, higher short circuit current density ( $$I_{sc}$$ ) of 0.89 mA cm−2 and higher fill factor ( $${\text{ff}}$$ ) of 0.67, indicating that the photovoltaic characteristics of alizarin excelled that of purpurin.

A new sorbent based on MWCNTs modification for separation/preconcentration of trace amounts of Cd(II), Cr(III), Cu(II), Ni(II), and Pb(II) and their determination by flame atomic absorption spectrometry

A new solid phase extraction (SPE) method has been developed for the separation/preconcentration and determination of lead, cadmium, chromium, nickel, and copper ions using a new sorbent. The method is based on the application of multiwalled carbon nanotubes modified with ethylenediamine-N,N-diacetic acid (MWCNTs-EDDA) as a selective sorbent in SPE for the separation and preconcentration of Pb(II), Ni(II), Cd(II), Cu(II), and Cr(III). The determination of these heavy metals was followed by flame atomic absorption spectrometry (FAAS). All quantitative determinations were performed by FAAS, and surface modification of synthesized adsorbents has been confirmed on the basis of characterization with Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The parameters such as pH, amount of adsorbent, shaking time, eluent type and its concentration, and matrix effect have been investigated and optimized. The maximum adsorption capacity of the adsorbent at optimum conditions was found to be 51.7, 67.6, 49.9, 57.8, and 62.3 mg g-1 for Cd(II), Cr(III), Cu(II), Ni(II), and Pb(II), respectively. In the presented study, MWCNTs were functionalized by EDDA and it was applied as an adsorbent for the separation and preconcentration of trace level of Pb, Ni, Cd, Cu, and Cr ions. This method is effective, selective, rapid, and simple for the determination of trace amounts of Pb, Ni, Cd, Cu, and Cr ions and can be successfully applied to analyze the trace amounts of mentioned ions in wastewater and herbal samples without evident interference from the complex matrix. Furthermore, the sorption has high capacity, and the precision and accuracy of the method are also satisfactory.

Kinetic and mechanism of the oxidation of chromium(III) complex with anthranil-N,N-diacetic acid by periodate ion in acidic aqueous solutions

The kinetics of oxidation of [CrIII(atda)(H2O)2] (atda = anthranil-N,N-diacetato) complex by IO 4 − was studied spectrophotometrically in aqueous solutions with pH range 2.20–3.34, 0.30 M ionic strength and in 20.0–40.0°C temperature range. The rate law of the reaction exhibited saturation kinetics. Values of the rate constant for the electron transfer process, the equilibrium constant for dissociation of [CrIII (atda)(H2O)2] to [CrIII (atda) (H2O)OH]+ + H+ and the pre-equilibrium formation constant were calculated. The thermodynamic activation parameters are reported. It is proposed that electron transfer proceeds through an inner-sphere mechanism via coordination of the IVII to chromium(III).

High-Temperature Laboratory Testing of Illitic Sandstone Outcrop Cores With HCl-Alternative Fluids

Summary Illitic sandstone reservoirs are sensitive to hydrochloric-acid (HCl) -based fluids. When HCl contacts illite, it breaks down and causes fines migration and formation damage. The migration of fines through the porous media will block the pores, reduce permeability, and decrease the production rate of oil and gas wells. A thorough literature review showed that all clay minerals are essentially unstable in HCl at temperatures greater than 300°F. In turn, there is a need to search for stimulation fluids other than HCl to stimulate deep sandstone reservoirs. Alternative fluids to HCl/hydrofluoric (HF) mud acids were introduced to stimulate and remove the damage from illitic sandstone reservoirs. These fluids are chelating agents such as hydroxyl ethylene diaminetriacetic acid (HEDTA) and glutamic acid-N,N-diacetic acid (GLDA). In this study, sandstone cores with different illite contents were examined. Illite contents of 1, 10, 14, and 18 wt% of the sandstone cores were used in the coreflood experiments at 300°F. Different combinations of GLDA/HF were tested to determine the optimum ratio of chelate/HF. Computed tomography scans and permeability measurements before and after the treatment were used to assess the effectiveness of each fluid in removing the damage and in the stimulation of the sandstone cores. The results show that 15 wt% HCl caused severe damage to sandstone cores with different illite contents. GLDA and HEDTA solutions showed a good compatibility with the illitic sandstone cores, with up to 18 wt% at 300°F. Permeability measurements showed that GLDA performed better than HEDTA at a pH of 4 and at the same molar concentration. The optimum ratio of GLDA/HF concentration was found to be 20 wt% GLDA/1 wt% HF, which gives the maximum increase in core permeability. No deconsolidation was noted with the two chelates tested. The results obtained from this study will significantly improve the outcome of acid treatments in illitic sandstone reservoirs at high temperatures.

Preliminary Study on the Effect of Ethylene Diamine- n, n-diacetic Acid on Methane Gas Production Rate from Cow Manure

In an effort to improve methane gas production rate from cattle slurry; ethylene diamine- N, N-diacetic acid chelating ligand was introduced into the digester system. Experimental analysis involving the determination of trace metals, pH and methane gas yield, were carried out with the use of the Flame Atomic Absorption Spectrophotometer and Biogas5000 analyser. The results showed that there was an increase in the pH of the system; the amount of methane gas yield equally increased by 12% and the Hydraulic Retention Time decreased from 50 days to 25 days on addition of ethylene diamine- N, N-diacetic acid chelating ligand. Also, increasing the concentration of the chelating ligand further decreased the HRT of the digester system from 25 days to 19days. Concentration of trace metals like Iron, Cobalt and Nickel within the digester system ranged from 0.001-0.050 mg/L; these metals reacted with ethylene diamine- N, N-diacetic acid chelating ligand to form metal chelates. The metal chelate formed resulted in the catalysis of the hydrolysis stage (which is the rate determining step) of the anaerobic digestion process. Thus, the decrease in HRT was due to the metal chelate catalysis of the hydrolysis stage of the anaerobic digestion process were the metal chelate formation served as the driving force in the solvolysis process.

Challenges During Shallow and Deep Carbonate Reservoirs Stimulation

Carbonate reservoir stimulation has been carried out for years using HCl or HCl-based fluids. High HCl concentration should not be used when the well completion has Cr-based alloy in which the protective layer is chrome oxide which is very soluble in HCl. HCl or its based fluids are not recommended either in shallow reservoirs where the fracture pressure is low (face dissolution) or in deep reservoirs where it will cause severe corrosion problems to the well tubular. Different chelating agents have been proposed to be used as alternatives to HCl in the cases that HCl cannot be used. Chelating agents, such as HEDTA (hydroxyl ethylene diamine triacetic acid) and GLDA (glutamic –N, N-diacetic acid), have been used to stimulate carbonate cores. The benefits of chelating agents over HCl are the low reaction, low leak-off rate, and low corrosion rates. In this study, the different equations and parameters that can be used in matrix acid treatment were summarized to scale up the laboratory conditions to the field conditions. The conditions where HCl or chelating agents can be used were optimized and in this paper. The leak-off rate was determined using the data from coreflood experiments and computed tomography (CT) scans. Indiana limestone cores of average permeability of 1 md and core lengths of 6 and 20 in. were used in this study. Chelating agents will be used at pH value of 4 and at concentration of 0.6M, and their performance will be compared with the 15 wt.% HCl. The experimental results showed that HCl has high leak-off rate and caused face dissolution at low injection rate. The model to scale up the linear coreflood results to radial field conditions was developed and can be used to design for the optimum conditions of the matrix acid treatments. Chelating agents can be used to stimulate shallow reservoirs in which HCl may cause face dissolution, because they can penetrate deep with less volume and also they can be used in deep reservoirs where HCl may cause severe corrosion to the well tubular.

Bioavailability of Nutrients for Improved Methane gas Production by Addition of Chelating Ligands

Our irreplaceable fossil fuels are fast diminishing. Therefore, an important precautionary measure will be to develop renewable energy sources. Biogas is renewable and an environmentally friendly alternative energy. This research work focused on addition of chelating ligands in order to improve methane gas yield, and decrease concentration of Volatile Fatty Acid produced within digester systems. The experimental analysis carried out involved the use of Flame Atomic Absorption Spectrophotometer , Biogas5000 analyser and other classical analytical tools. The concentration of trace metals presents namely Iron, Cobalt, and Nickel ranged from 0.001-0.050 mg/L. On addition of chelating ligands, Ethylene diamine-N,N-diacetic acid, Nitrilotri-acetic acid and Diethylenetriamine-pentaacetic acid, an increase in the Methane yield was recorded which ranged from 2-15%. The Volatile Fatty Acid concentration was generally low with values for Ethylene diamine-N,N- diacetic acid, Nitrilotri-acetic acid and Diethylenetriamine-pentaacetic acid given as 476.05 mg/L, 671.96 mg/L, and 737.63 mg/L respectively; with pH ranging from 6-7.5. The improvement in methane gas yield was due to the increased bioavailability of essential nutrients on addition of chelating ligands which invariably promoted the growth and stability of the methane producing bacteria thereby, improving methane production. The Volatile Fatty Acid values which were generally lower than 2000 mg/L are implicated in the high methane gas yield observed.

Soil Washing Enhanced by Humic Substances and Biodegradable Chelating Agents

Industrial timber treatment sites have resulted in widespread soil contamination by Cu, Cr, and As, presenting potential long-term liability and associated risks to human health and the environment. This study evaluated the roles of natural humic substances (lignite-derived humic substances, standard and commercially available humic acids) and biodegradable chelating agents (ethylenediamine-N,N-disuccinic acid (EDDS) and glutamic-N,N-diacetic acid (GLDA)) for soil washing. Batch kinetic experiments revealed that humic substances promoted Cu extraction at pH 8, but they were significantly adsorbed on the soil at pH 4, possibly posing impediment to soil remediation. The metal extraction by EDDS and GLDA was comparable to that of EDTA (ethylenediamine-tetraacetic acid), and it was more effective at pH 4 than pH 8, probably due to acidic dissolution of metal precipitates and oxides. Metal distribution analysis indicated that the carbonate fraction of Cu and the oxide fraction of As and Cr were mainly extracted, while the exchangeable fraction of Cu increased. The residual leachability tests showed that humic substances reduced the Cu and As leachability but the reduction was insufficient. In contrast, EDDS was able to reduce the leachate concentrations of Cu and As to below 5 mg L−1, meeting the waste acceptance criteria for landfill disposal. Nevertheless, soil washing methods and remediation strategy may need further modifications to facilitate site restoration and promote soil recycling.

Metal distribution and spectroscopic analysis after soil washing with chelating agents and humic substances

Biodegradable chelating agents ([S,S]-ethylenediamine-N,N-disuccinic acid (EDDS) and glutamic-N,N-diacetic acid (GLDA)) and natural humic substances (lignite-derived, standard, and commercially available humic acids) are potentially useful for enhancing soil remediation of timber treatment sites. This study integrated macroscopic and spectroscopic analyses to assess their influence on the distribution and chemical speciation of the remaining metals as well as their interaction with the soil surface after 48-h washing of a field-contaminated soil. The results demonstrated that EDDS and GLDA were an appealing alternative to non-biodegradable ethylenediamine-tetraacetic acid, but the three humic substances were less effective. As shown by sequential extractions, Cu was primarily extracted from the carbonate fraction while Cr and As extraction resulted from (co-)dissolution of the oxide fraction. As a result, the relative proportion of strongly bound organic matter and residual fractions increased by 7-16 %. However, it was noteworthy that the exchangeable fraction also increased by 5-11 %, signifying that a portion of the remaining metals was destabilized by chelating agents and transformed to be more labile in the treated soil. The X-ray photoelectron spectroscopy spectra confirmed the substantial removal of readily accessible Cu from the soil surface, but Cr maintained its original chemical forms of trivalent chromium oxides and iron-chromium coprecipitates, whereas As remained as arsenic trioxide/pentoxide and copper arsenate precipitates. On the other hand, the absence of characteristic peaks of adsorbed carboxylate groups in the Fourier-transform infrared (FTIR) spectra inferred that the extent of adsorption of chelating agents and humic substances on the bulk soil was insufficient to be characterized by FTIR analysis. These results suggested that attention should be paid to the exchangeable fraction of Cu and oxides/coprecipitates of As prior to possible on-site reuse of the treated soil.

Novel potential agents for ulcerative colitis by molecular topology: suppression of IL-6 production in Caco-2 and RAW 264.7 cell lines

Ulcerative colitis (UC) is an immune-mediated chronic and relapsing intestinal inflammatory disease. Interleukin (IL)-6, a pro-inflammatory cytokine, plays a key role in the uncontrolled intestinal inflammatory process, which is a main characteristic of UC. In this work, a quantitative structure-activity relationship model based on molecular topology (MT) has been built up to predict the IL-6 mediated anti-UC activity. After an external validation of the model, a virtual screening of the MicroSource Pure Natural Products Collection and Sigma-Aldrich databases was carried out looking for potential new active compounds. From the entire set of compounds labeled as active by the model, four of them, namely alizarin-3-methylimino-N,N-diacetic acid (AMA), Calcein, (+)-dibenzyl-L-tartrate (DLT), and Ro 41-0960, were tested in vitro by determination of IL-6 production in two cell lines (RAW 264.7 and Caco-2). The results demonstrate that three of them were able to significantly reduce IL-6 levels in both cell lines and particularly one, namely Ro 41-0960. These results confirm MT's efficacy as a tool for the selection of compounds potentially active in UC.

Residual leachability of CCA-contaminated soil after treatment with biodegradable chelating agents and lignite-derived humic substances

The aim of this study was to enhance the soil remediation of timber treatment sites; the potential application of biodegradable chelating agents and humic substances as enhancing agents was assessed in terms of the residual leachability of chromium, copper and arsenic (CCA). This study applied four leachability tests on a field-contaminated soil after 48-h washing with ethylenediamine-N,N-disuccinic acid (EDDS), glutamic-N,N-diacetic acid, ethylenediaminetetraacetic acid and humic substances derived from lignite and two other sources. It was noteworthy that the reduction in the total metal concentrations after soil washing was not predictive of the leaching behaviour. When assessed by toxicity characteristic leaching procedure (TCLP) and waste extraction test (WET), Cu and As leachability was decreased as a result of their extraction by soil washing. By contrast, when assessed by synthetic precipitation leaching procedure (SPLP) and European Council Waste Acceptance Criteria (ECWAC) tests, Cu and As leachability was found to increase, probably because the effect of destabilization of residual metals during soil washing was more observable in unbuffered leaching solutions. On the other hand, Cr leachability was acceptably low in TCLP and WET but still exceeded drinking water standard in SPLP and ECWAC tests. The three chelating agents were able to meet the criteria for Cu in all leachability tests, while the limits of As concentrations could only be met by EDDS in TCLP test. The three humic substances reduced the leachate concentrations of Cu and As without destabilizing the residual metals; however, the reduction was insufficient to meet the required limits in all leachability tests considered.

Spectroscopic study on the sonodynamic and sonocatalytic damage of anthraquinone derivants to bovine serum albumin under ultrasonic irradiation

In this work, three anthraquinone derivants (Alizarin: 1,2-dihydroxy-9, 10-anthraquinone, Alizarin–DA: 1,2-dihydroxy-9, 10-anthraquinone-3-aminomethyl-N, N-diacetic acid and Alizarin–DA–Fe: 1,2-dihydroxy-9, 10-anthraquinone-3-aminomethyl-N, N-diacetate-Ferrous(III)) were used to study the sonodynamic and sonocatalytic damage of bovine serum albumin (BSA) molecules according to the hyperchromic effect of UV–vis spectra and quenching effect of intrinsic fluorescence. Meanwhile, some influencing factors such as ultrasonic irradiation time, anthraquinone derivants concentration and ionic strength on the damage of BSA molecules were also considered. The results show that the synergetic effect of anthraquinone derivants and ultrasonic irradiation can efficiently damage the BSA molecules. Finally, some special radical scavengers were used to determine the kind of generated reactive oxygen species (ROS) in the presence of three anthraquinone derivants under ultrasonic irradiation. The results show that the ROS, at least, including singlet oxygen ( 1O 2) and hydroxyl radicals (OH) are generated during the sonodynamic and sonocatalytic processes. It is wished that this paper could offer some valuable references for the application of anthraquinone derivants in sonodynamic therapy (SDT) and sonocatalytic therapy (SCT) for tumor treatment.

Optimum Injection Rate of A New Chelate That Can Be Used To Stimulate Carbonate Reservoirs

Summary Different chelating agents were used as alternatives for hydrochloric acid (HCl) in matrix acidizing to create wormholes in carbonate formations. Previous studies demonstrated the use of ethylenediaminetetraacetic acid (EDTA), hydroxy ethylenediaminetriacetic (HEDTA), and glutamic acid-N,N-diacetic acid (GLDA) as standalone stimulation fluids to stimulate carbonate reservoirs. The main problem of using EDTA and HEDTA is their low bio-degradability. GLDA was introduced as a standalone stimulation fluid for deep carbonate reservoirs where HCl can cause corrosion and face dissolution problems. In this study, calcite cores 1.5 in. in diameter and 6 or 20 in. in length were used to determine the optimum conditions where the GLDA can break through the core and form wormholes. GLDA solutions with pH values of 1.7, 3, and 3.8 were used. The optimum conditions of injection rate and pH were determined using coreflood experiments. Damköhler number was determined using the wormhole length and diameter from the CT scan 3D and 2D images. GLDA was compared with chelates that are used in the oil industry such as EDTA and HEDTA. GLDA also was used to stimulate parallel cores with different permeability ratios (up to 6.25). GLDA was found to be very effective in creating wormholes at pH = 1.7, 3, and 3.8; at different injection rates; and at temperatures up to 300°F. Increasing the temperature increased the reaction rate and less volume of GLDA was required to break through the core and form wormholes. Unlike HCl, in GLDA there was no face dissolution or washout in the cores even at low injection rates (0.5 cm3/min). An optimum injection rate and Damköhler number were found at which the pore volume (PV) required to create wormholes was the minimum. GLDA at pH 1.7 and 3 created wormholes with a small number of PV (at 1 cm3/min, GLDA at pH 1.7 required 1.5 PV at 300°F, and at pH 3 it required 1.8 PV). Compared with acetic acid, the volume of GLDA at pH 3 required to create wormholes was less than that required with acetic acid at the same conditions. GLDA was found to be effective in stimulating parallel cores up to 6.25 permeability contrast (final permeability/initial permeability).

Spectroscopic Analysis of the Interactions of Anthraquinone Derivatives (Alizarin, Alizarin-DA and Alizarin-DA-Fe) with Bovine Serum Albumin (BSA)

In this paper, three anthraquinones (alizarin (1,2-dihydroxy-9,10-anthraquinone), alizarin-DA (1,2-dihydroxy-9,10-anthraquinone-3-aminomethyl-N,N-diacetic acid) and alizarin-DA-Fe (1,2-dihydroxy-9,10-anthraquinone-3-aminomethyl-N,N-diacetate-ferric(III))) with a tricyclic anthraquinone planar structure are used as quenchers, to study their interaction with bovine serum albumin (BSA) molecules by fluorescence spectroscopy. The results show that these three anthraquinones can bind to BSA molecules efficiently but the stabilities decrease in the order alizarin, alizarin-DA and alizarin-DA-Fe. In addition, synchronous fluorescence spectroscopy indicates that the tryptophan (Trp) residues of BSA molecules are more accessible to alizarin and alizarin-DA than the tyrosine (Tyr) residues, but both have similar accessibility to alizarin-DA-Fe.

First example of well-characterized Re and 99mTc tricarbonyl complexes of ciprofloxacin and norfloxacin in the development of infection-specific imaging agents

Aiming at the development of 99mTc-based infection-specific imaging agents, the synthesis and characterization of rhenium and technetium-99m tricarbonyl complexes with derivatized ciprofloxacin and norfloxacin is hereby reported. The ligands were prepared by coupling the tridentate chelator picolylamino- N, N-diacetic acid (PADA) with the piperazinyl (NH) nitrogen of ciprofloxacin or norfloxacin, through the employment of the PADA anhydride. The corresponding rhenium complexes were synthesized using the fac-[NEt 4] 2[ReBr 3(CO) 3] precursor and were fully characterized by elemental analysis and NMR spectroscopy. X-ray crystallography of the ciprofloxacin complex showed that the geometry about rhenium is distorted octahedral defined by the NNO donor atom set of the tridentate chelator and the three carbonyl groups. The analogous technetium-99m complexes were prepared quantitatively through the use of the fac-[ 99mTc(H 2O) 3(CO) 3] + precursor and their structure was established by comparative HPLC studies using the well-characterized rhenium complexes as reference. Preliminary studies with the technetium-99m complexes showed high bacterial uptake in vitro.