scholarly journals The Application of Alginate Coated Iron Hydroxide for the Removal of Cu(II) and Phosphate

2019 ◽  
Vol 9 (18) ◽  
pp. 3835 ◽  
Author(s):  
Hee-Gon Kim ◽  
Feng He ◽  
Byungryul An
Keyword(s):  
Removal Rate ◽  
Iron Hydroxide ◽  
Ph Dependence ◽  
Ferric Hydroxide ◽  
Critical Factor ◽  
Cost Effective ◽  
Phosphate Removal ◽  
Alginate Concentration ◽  
Multiple Materials ◽  
High Concentrations

The removal of both cation and anion contaminants in solution typically requires separate processes or multiple materials, resulting in added complexity and higher operational costs. A cost effective and environmental friendly hybrid adsorbent material has been developed for the removal of Cu(II) and phosphate from the solution. Ferric hydroxide (FHO) was prepared by precipitation methods and then dissolved alginate, a biopolymer, was coated on the surface of the FHO particles to generated FHO-A. In the preparation of FHO-A, the alginate concentration is a critical factor in keeping the FHO-A particles suspended in solution where high concentrations of alginate act as a stabilizer and the FHO-A particles are not settled by gravity. The Cu(II) removal efficiency was wholly dependent on the concentration of alginate via the interaction with the polymer carboxyl groups and was not influenced by the concentration of FHO. Conversely, alginate was not involved in the removal of phosphate and instead, FHO was found to be critical for phosphate removal through electrostatic forces. According to FTIR, the new peaks at 1394 and 1593 cm−1 after coating indicated that the alginate was appended to the surface of the FHO. The shift of peak from 1593 to 1588 cm−1 after Cu(II) adsorption confirms the presence of a Cu-carboxylate interaction. The adsorption of Cu(II) was completed within 5 min, which is very similar to nanoparticle mediated sorption processes. In comparison to Cu(II), the presence of alginate retards the phosphate removal rate. Further, pH dependence was observed in the process, where increasing pH results in increased Cu(II) and decreased phosphate removal rates due to alginate deprotonation and the surface charge effects, respectively. The slowed phosphate sorption rate and shifted peaks in the FTIR spectrum confirmed that the layer of alginate was coated on the FHO particle.

Influencing Factors of the In Situ Formed Iron Hydroxide (FeOxHy) on the Removal of Phosphate by Coagulation and Adsorption

2013 ◽  
Vol 864-867 ◽  
pp. 1772-1778 ◽  
Author(s):  
Li Hua Sun ◽  
Tian Min Yu ◽  
Xue Ru Chen ◽  
Xiao Lu Qi ◽  
Ya Jun Zhang
Keyword(s):  
Ph Value ◽  
Removal Rate ◽  
Iron Hydroxide ◽  
Phosphate Removal ◽  
Chemical Action ◽  
Mass Unit ◽  
Molar Ratios ◽  
Hydroxyl Ion ◽  
Water Ph

This study prepared the in situ formed iron hydroxide (in situ FeOxHy) by the interactions between Fe3+ and OH- at different molar ratios of 1:0, 1:1, 1:2 and 1:3. The influences of molar ratios and pH on the removal of phosphate were investigated and the surface of in situ FeOxHy before and after adsorption was analyzed. The phosphate removal rate with mass unit iron hydroxide is greater at the molar ratios of 1:3 between Fe3+ and OH-. The phosphate removal rate is maximum at the pH 6~7. The compatibility of iron hydroxide towards raw water pH value is better when the proportion of hydroxyl ion is greater. The disposal effect is good at the pH 4~9. The iron hydroxide formed at different molar ratios is not definitive shape and it can remove phosphate by the chemical action of adsorption and sedimentation.

New Technologies for Decontamination of Radioactive Substances Scattered by Nuclear Accident / Nowe Technologie Dekontaminacji Radioaktywnych Substancji Rozproszonych Przez Awarie Nuklearna

2013 ◽  
Vol 58 (1) ◽  
pp. 283-290 ◽  
Author(s):  
Y. Nishizaki ◽  
H. Miyamae ◽  
S. Ichikawa ◽  
K. Izumiya ◽  
T. Takano ◽  
...  
Keyword(s):  
Radioactive Waste ◽  
New Technologies ◽  
Ferric Hydroxide ◽  
Nuclear Accident ◽  
Radioactive Cesium ◽  
Cesium Ions ◽  
Naoh Solution ◽  
High Concentrations ◽  
Water Rinsing

Our effort for decontamination of radioactive cesium scattered widely by nuclear accident in March 2011 in Fukushima, Japan has been described. Radioactive cesium scattered widely in Japan has been accumulating in arc or plasma molten-solidified ash in waste incinerating facilities up to 90,000 Bq/kg of the radioactive waste. Water rinsing of the ash resulted in dissolution of cesium ions together with high concentrations of potassium and sodium ions. Although potassium inhibits the adsorption of cesium on zeolite, we succeeded to precipitate cesium by in-situ formation of ferric ferrocyanide and iron rust in the radioactive filtrate after rinsing of the radioactive ash with water. Because the regulation of no preservation of any kind of cyanide substances, cesium was separated from the precipitate consisting of cesium-captured ferric ferrocyanide and ferric hydroxide in diluted NaOH solution and subsequent filtration gave rise to the potassium-free radioactive filtrate. Cesium was captured by zeolite from the potassium-free radioactive filtrate. The amount of this final radioactive waste of zeolite was significantly lower than that of the arc-molten-solidified ash.

scholarly journals Phosphate Removal Using Polyethylenimine Functionalized Silica-Based Materials

2021 ◽  
Vol 13 (3) ◽  
pp. 1502
Author(s):  
Maria Xanthopoulou ◽  
Dimitrios Giliopoulos ◽  
Nikolaos Tzollas ◽  
Konstantinos S. Triantafyllidis ◽  
Margaritis Kostoglou ◽  
...  
Keyword(s):  
Sorption Capacity ◽  
Removal Rate ◽  
Phosphate Concentration ◽  
Phosphate Removal ◽  
Equilibrium Studies ◽  
Maximum Sorption Capacity ◽  
Algae Blooms ◽  
Maximum Sorption ◽  
Phosphate Anions ◽  
Adsorbent Dose

In water and wastewater, phosphate anions are considered critical contaminants because they cause algae blooms and eutrophication. The present work aims at studying the removal of phosphate anions from aqueous solutions using silica particles functionalized with polyethylenimine. The parameters affecting the adsorption process such as pH, initial concentration, adsorbent dose, and the presence of competitive anions, such as carbonate, nitrate, sulfate and chromate ions, were studied. Equilibrium studies were carried out to determine their sorption capacity and the rate of phosphate ions uptake. The adsorption isotherm data fitted well with the Langmuir and Sips model. The maximum sorption capacity was 41.1 mg/g at pH 5, which decreased slightly at pH 7. The efficiency of phosphate removal adsorption increased at lower pH values and by increasing the adsorbent dose. The maximum phosphate removal was 80% for pH 5 and decreased to 75% for pH 6, to 73% for pH 7 and to 70% for pH 8, for initial phosphate concentration at about 1 mg/L and for a dose of adsorbent 100 mg/L. The removal rate was increased with the increase of the adsorbent dose. For example, for initial phosphate concentration of 4 mg/L the removal rate increased from 40% to 80% by increasing the dose from 0.1 to 2.0 g/L at pH 7. The competitive anions adversely affected phosphate removal. Though they were also found to be removed to a certain extent. Their co-removal provided an adsorbent which might be very useful for treating waters with low-level multiple contaminant occurrence in natural or engineered aquatic systems.

scholarly journals Electrochemical Response of Glucose Oxidase Adsorbed on Laser-Induced Graphene

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1893
Author(s):  
Sónia O. Pereira ◽  
Nuno F. Santos ◽  
Alexandre F. Carvalho ◽  
António J. S. Fernandes ◽  
Florinda M. Costa
Keyword(s):  
Electron Transfer ◽  
Glucose Oxidase ◽  
Ph Dependence ◽  
High Surface ◽  
High Surface Area ◽  
Cost Effective ◽  
Great Promise ◽  
Glucose Detection ◽  
Half Wave ◽  
Electrochemical Transducers

Carbon-based electrodes have demonstrated great promise as electrochemical transducers in the development of biosensors. More recently, laser-induced graphene (LIG), a graphene derivative, appears as a great candidate due to its superior electron transfer characteristics, high surface area and simplicity in its synthesis. The continuous interest in the development of cost-effective, more stable and reliable biosensors for glucose detection make them the most studied and explored within the academic and industry community. In this work, the electrochemistry of glucose oxidase (GOx) adsorbed on LIG electrodes is studied in detail. In addition to the well-known electroactivity of free flavin adenine dinucleotide (FAD), the cofactor of GOx, at the expected half-wave potential of −0.490 V vs. Ag/AgCl (1 M KCl), a new well-defined redox pair at 0.155 V is observed and shown to be related to LIG/GOx interaction. A systematic study was undertaken in order to understand the origin of this activity, including scan rate and pH dependence, along with glucose detection tests. Two protons and two electrons are involved in this reaction, which is shown to be sensitive to the concentration of glucose, restraining its origin to the electron transfer from FAD in the active site of GOx to the electrode via direct or mediated by quinone derivatives acting as mediators.

Cucumber vs Ants: a Case Against the Myth of the Uses of Plant Extracts in Insect Pest Management

Sociobiology ◽  
2021 ◽  
Vol 68 (2) ◽  
pp. 5813
Author(s):  
Matan Shelomi ◽  
Bo-Jun Qiu ◽  
Lin-Ting Huang
Keyword(s):  
Plant Extracts ◽  
Scientific Evidence ◽  
Insect Pest ◽  
Management Strategies ◽  
Cost Effective ◽  
Detectable Effect ◽  
Realistic Situation ◽  
Potential Impact ◽  
High Concentrations ◽  
Ant Repellent

An accumulation of questionable scientific reports on the use of natural plant extracts to control household pest insects, using biologically irrelevant experimental designs and extremely high concentrations, has resulted in a publication bias: “promising” studies claiming readily available plants can repel various insects, including social insects, despite no usable data to judge cost-effectiveness or sustainability in a realistic situation. The Internet provides a further torrent of untested claims, generating a background noise of misinformation. An example is the belief that cucumbers are “natural” ant repellent, widely reported in such informal literature, despite no direct evidence for or against this claim. We tested this popular assertion using peel extracts of cucumber and the related bitter melon as olfactory and gustatory repellents against ants. Extracts of both fruit peels in water, methanol, or hexane were statistically significant but effectively weak gustatory repellents. Aqueous cucumber peel extract has a significant but mild olfactory repellent effect: about half of the ants were repelled relative to none in a control. While the myth may have a grain of truth to it, as cucumber does have a mild but detectable effect on ants in an artificial setup, its potential impact on keeping ants out of a treated perimeter would be extremely short-lived and not cost-effective. Superior ant management strategies are currently available. The promotion of “natural” products must be rooted in scientific evidence of a successful and cost-effective implementation prospect.

Piper nigrum Oil – Determination of Selected Terpenes for Quality Evaluation

Planta Medica ◽  
2018 ◽  
Vol 85 (03) ◽  
pp. 185-194 ◽  
Author(s):  
Mei Wang ◽  
Amar Chittiboyina ◽  
Jon Parcher ◽  
Zulfiqar Ali ◽  
Paul Ford ◽  
...  
Keyword(s):  
Quality Evaluation ◽  
Geographical Location ◽  
Chemical Characterization ◽  
Principal Component ◽  
Cost Effective ◽  
Black Pepper ◽  
Piper Nigrum ◽  
Ms Analysis ◽  
Chemical Profiles ◽  
High Concentrations

AbstractThe growing demand and commercial value of black pepper (Piper nigrum) has resulted in considerable interest in developing suitable and cost-effective methods for chemical characterization and quality evaluation purposes. In the current study, an extensive set of oil samples (n = 23) that were extracted by steam distillation from black pepper seeds was investigated to compare the chemical profiles of samples originating from nine major producing countries, as well as to identify potential chemical markers for quality evaluation. The twenty-two most abundant volatile compounds, mainly terpenes, in these oils were determined by conventional GC/MS analysis. Principal component analysis with this set of data revealed distinct clusters for samples that originated from China and Malaysia. Relatively low concentrations of sabinene (< 0.2%) and high concentrations of 3-carene (10.9 – 21.1%) were observed in these samples, respectively, compared to oil samples from other countries. The enantiomeric distributions of key terpene markers, viz., β-pinene, sabinene, limonene, and terpinen-4-ol, were determined by chiral GC/MS analysis. Interestingly, for these four monoterpenes, levo-isomers were found to be predominant, emphasizing the highly conserved enzymatic processes occurring in P. nigrum. Moreover, consistent enantiomeric ratios ((−) isomer/(+) isomer) of 92.2 ± 3.0% for β-pinene, 94.8 ± 2.8% for sabinene, 60.7 ± 1.1% for limonene, and 78.3 ± 1.3% for terpinen-4-ol were observed, independent of geographical location. These results demonstrate the potential of using stereospecific compositions as chiral signatures for establishing the authenticity and quality of black pepper oil.

Comparison of Coal Ash and Activated Carbon for Removal of Humic Acid from Aqueous Solution

2013 ◽  
Vol 864-867 ◽  
pp. 1509-1512
Author(s):  
Xue Mei Zhang ◽  
Yan Zhang ◽  
Di Fan
Keyword(s):  
Aqueous Solution ◽  
Humic Acid ◽  
Activated Carbons ◽  
Removal Rate ◽  
Coal Ash ◽  
Cost Effective ◽  
Solution Ph ◽  
Adsorption Behaviors ◽  
Calcium Loading ◽  
Working Solution

This paper presents the adsorption behaviors of humic acid (HA) on coal ashes and powdered activated carbons (PACs). A bituminous coal, with or without calcium-loading, was used as a feedstock for coal ash preparation. The working solution of HA with a concentration of 20 mg/L was used in all adsorption tests. The results showed that calcium-enriched coal ash (CECA) gave rise to the removal rate of HA as high as 84.05%, much higher than those of raw coal ash (RCA) and PACs. The impacts of solution pH and adsorbent dosage on HA adsorption capacity were also investigated. It was found that lower pH facilitated to the removal of HA from aqueous solution by means of CECA, and the optimal CECA dosage was about 1.0g/L at pH 7.00. The data obtained in this study suggested that calcium-enriched coal ash could be useful and cost-effective in the treatment of wastewaters containing HA-like organic macro-molecules.

scholarly journals Synthesis of bisquinolines through conventional and unconventional energy sources

2011 ◽  
Author(s):  
◽  
Talent Raymond Makhanya
Keyword(s):  
Schiff Base ◽  
Microwave Irradiation ◽  
Critical Factor ◽  
Cost Effective ◽  
Synthetic Methods ◽  
Parasite Life Cycle ◽  
Immunodeficiency Virus ◽  
Alkaline Conditions ◽  
Tropical Areas ◽  
Resistant Strains

Malaria, the most prevalent parasitic disease, is considered a neglected disease owing to insufficient research and development in synthesis and therapy worldwide. Therapy failures are frequent and are due to a variety of factors such as the intrinsic characteristics of the disease, conditions of transmission, and the difficult control of spreading through tropical areas. Primary factors are the complexity of the parasite life cycle and the development of drug resistance. Another critical factor is the increasing number of immune-compromised patients that suffer from malaria and human immunodeficiency virus (HIV) co-infections. Most of the drugs currently available to treat malaria are quinoline derivatives modelled on the quinine molecule, found in the bark of Cinchona trees. Over the last 50 years the use of quinine has declined owing to the development of synthetic 4-aminoquinolines such as chloroquine. However, the malaria parasite is rapidly becoming resistant to the drugs currently available. Recently bisquinoline compounds were found more potent than chloroquine against both chloroquine-sensitive and resistant strains of malaria; this improved efficacy and prompted an increased interest in the design of these anti-malarial drugs. Although several synthetic methods are available to synthesise bisquinolines, we report the synthesis of bisquinolines from simple, readily available and cost- effective starting compounds. The synthesis was accomplished in four reaction steps using the Claisen condensation, Vilsmeir-Haack reaction, formation of a Schiff base and thermal cyclization, sequentially. We used a conventional energy source and microwave irradiation for the synthesis, wherever possible, of 2, 4-dichloro-3, 4'-biquinoline and 2, 4-dichloro-7'-methoxy-3, 4'-biquinoline. In the first step, 3-acyl-2, 4-dihydroxyquinoline is synthesised from an equimolar mixture of methyl-2-aminobenzoate and ethyl acetoacetate by microwave irradiation for 3 minutes; the yield is 90 % whereas by 6 hours refluxing the yield is 75 %. This is followed by the synthesis of 3-chloro-3-(2,4-dichloroquinolin-3yl) acrylaldehyde, by combining DMF and POCl3 at 00C to form the electrophile which reacts with 3-acyl-2,4-dihydroxyquinoline under microwave irradiation for 5 minutes; the yield is 65 % whereas by 6 hours refluxing the yield is 50 %. In the next step, several protocols to prepare a Schiff base 3-chloro-3-(2, 4-dichloroquinolin-3-yl) allylidene aniline are investigated with the best yield of 75% obtained by microwave irradiation for 5 minutes. Subsequently three aniline derivatives viz, 4-methoxyaniline, 4-chloroaniline and 4-methylaniline, are used as substrate to prepare 3-chloro-3-(2,4-dichloroquinolin-3-yl) allylidene-4-methoxyaniline, 3-chloro-3-(2 ,4-dichloroquinolin-3-yl) allylidene-4-methylaniline and 3-chloro-3-(2, 4-dichloroquinolin-3-yl) allylidene-4-chloro aniline at 68, 78 and 64 % yield, respectively. In the final step, 2, 4-dichloro-3, 4'-biquinoline is prepared; several methods were investigated, however, the best yield is 24 % which is obtained under alkaline conditions in the presence of K2CO3 and DMF by microwave irradiation for 10 minutes. The 2, 4-dichloro-7'-methoxy-3, 4'-biquinoline derivative is also prepared in 18 % yield under the same alkaline conditions. The outline of the total synthesis of bisquinoline is presented graphically below.

scholarly journals A Critical Factor for Quantifying Proteins in Unmodified Gold Nanoparticles-Based Aptasensing: The Effect of pH

Chemosensors ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 98
Author(s):  
Dai Lu ◽  
Dong Zhang ◽  
Qian Zhao ◽  
Xiangyang Lu ◽  
Xingbo Shi
Keyword(s):  
Gold Nanoparticles ◽  
Limit Of Detection ◽  
Protein Detection ◽  
Critical Factor ◽  
Cost Effective ◽  
Protein Corona ◽  
Target Protein ◽  
Universal Method ◽  
Salt Addition ◽  
Positively Charged

Unmodified gold nanoparticles (AuNPs)-based aptasensing (uGA) assay has been widely implemented in the determination of many different targets, but there are few reports on protein detection using uGA. Here, we designed a uGA assay for protein detection including the elimination of interfering proteins. Positively charged protein can be absorbed directly on the surface of AuNPs to form “protein corona”, which results in the aggregation of AuNPs even without salt addition, thereby preventing target protein detection. To overcome this problem, we systematically investigated the effect of modifying the pH of the solution during the uGA assay. A probe solution with a pH slightly higher than the isoelectric points (pI) of the target protein was optimal for protein detection in the uGA assay, allowing the aptamer to selectively detect the target protein. Three proteins (beta-lactoglobulin, lactoferrin, and lysozyme) with different pI were chosen as model proteins to validate our method. Positively charged interfering proteins (with pIs higher than the optimal pH) were removed by centrifugation of protein corona/AuNPs aggregates before the implementation of actual sample detection. Most importantly, the limit of detection (LOD) for all three model proteins was comparable to that of other methods, indicating the significance of modulating the pH. Moreover, choosing a suitable pH for a particular target protein was validated as a universal method, which is significant for developing a novel, simple, cost-effective uGA assay for protein detection.

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