Selection and Impact Mechanism of Washing Agents for Chromium Contaminated Building Waste

2012 ◽  
Vol 178-181 ◽  
pp. 1083-1092
Author(s):  
Xing Run Wang ◽  
Yan Xia Zhang ◽  
Jian Min Shu
Keyword(s):  
Particle Size ◽  
Citric Acid ◽  
Organic Acid ◽  
Hexavalent Chromium ◽  
Removal Rate ◽  
Trivalent Chromium ◽  
Acid Condition ◽  
Impact Mechanism ◽  
Removal Mechanisms

With the building wastes contaminated by chromium in Haibei Chemical Plan in China as objects, it studied the contents of total Cr and Cr (Ⅵ) of different sizes, analyzed the effect of 6 different washing agents, discussed the removal mechanisms of 6 different washing agents for Cr in various forms, and finally selected applicable washing agent. As the results, particle size had little impact on the contents of total Cr and Cr (Ⅵ); after one washing with water, the removal rate of total Cr and Cr (Ⅵ) was 75% and 78%, respectively, and after the second washing with 6 agents, the removal rate of citric acid was the highest, above 90% for total Cr and above 99% for hexavalent chromium; the pH of building wastes were reduced by citric acid, and under acid condition, hexavalent chromium was reduced to trivalent chromium spontaneously by organic acid, which led to better removal rate of acid soluble Cr and reducible Cr; due to the complexing action, citric acid had best removal rate for oxidizable trivalent chromium. In conclusion, citric acid is the most applicable second washing agent for building wastes.

scholarly journals Effect and Removal Mechanisms of 6 Different Washing Agents for Building Wastes Containing Chromium

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Wang Xing-run ◽  
Zhang Yan-xia ◽  
Wang Qi ◽  
Shu Jian-min
Keyword(s):  
Particle Size ◽  
Citric Acid ◽  
Organic Acid ◽  
Hexavalent Chromium ◽  
Removal Rate ◽  
Trivalent Chromium ◽  
Acid Condition ◽  
Removal Mechanisms

With the building wastes contaminated by chromium in Haibei Chemical Plan in China as objects, we studied the contents of total Cr and Cr (VI) of different sizes, analyzed the effect of 6 different washing agents, discussed the removal mechanisms of 6 different washing agents for Cr in various forms, and finally selected applicable washing agent. As per the results, particle size had little impact on the contents of total Cr and Cr (VI); after one washing with water, the removal rate of total Cr and Cr (VI) was 75% and 78%, respectively, and after the second washing with 6 agents, the removal rate of citric acid was the highest, above 90% for total Cr and above 99% for hexavalent chromium; the pH of building wastes were reduced by citric acid, and under acid condition, hexavalent chromium was reduced to trivalent chromium spontaneously by organic acid, which led to better removal rate of acid soluble Cr and reducible Cr; due to the complexing action, citric acid had best removal rate for oxidizable trivalent chromium. In conclusion, citric acid is the most applicable second washing agent for building wastes.

scholarly journals Reduction of Hexavalent Chromium by Ferrous Ions to Trivalent Chromium in Presence of Organic Acid Additives

2015 ◽  
Vol 27 (11) ◽  
pp. 3998-4006
Author(s):  
A.M. Ahmed ◽  
Mervette El Batouti ◽  
Mona A. Darweesh ◽  
Said M. Said
Keyword(s):  
Organic Acid ◽  
Hexavalent Chromium ◽  
Trivalent Chromium ◽  
Ferrous Ions

Evaluation of Microwave-Assisted Organic Acid Separation of Organic Sulfur from High Sulfur Coal

2021 ◽  
Author(s):  
Chaoshun Jiang ◽  
Jin Liu ◽  
Shen Hao ◽  
Zheng Pang ◽  
Zhi Wang ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Citric Acid ◽  
Oxalic Acid ◽  
Microwave Irradiation ◽  
Organic Acids ◽  
Organic Acid ◽  
Removal Rate ◽  
Organic Sulfur ◽  
Microwave Assisted ◽  
Operation Conditions

Abstract To explore the feasibility of organic acid removal of organic sulfur from high sulfur coal, three organic acids, oxalic acid, citric acid and ascorbic acid, were selected as desulfurization reagents. Combined with microwave irradiation technology, desulfurization experiments of high-sulfur coal treated with nitric acid were conducted. The orthogonal experimental results showed that microwave synergistic citric acid desulfurization had a better desulfurization effect. The removal rate of organic sulfur was 55.47% when the operation conditions of the reaction were 1 mol/L, 90 ℃ and 1000 W for 7 min. The desulfurization efficiency of oxalic acid and ascorbic acid was not good, and the removal efficiencies of organic sulfur were 32.35% and 21.37%, respectively. Fourier transform infrared spectroscopy showed that sulfones and sulfoxides were partially reduced and that the removal effect of thiophene was poor. X-ray photoelectron spectroscopy showed that the mercapto group in the mercaptan combined with hydrogen ions and escaped in the form of H2S. The content of aromatic thioether and aromatic thiol in the coal treated with microwave irradiation was only 0.1%. Research indicates that microwave-assisted organic acid removal of organic sulfur is feasible, and researchers can explore more efficient organic acids as desulfurization reagents based on this study.

scholarly journals Crude Citric Acid of Trichoderma asperellum: Tomato Growth Promotor and Suppressor of Fusarium oxysporum f. sp. lycopersici

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 222
Author(s):  
Abdulaziz A. Al-Askar ◽  
WesamEldin I. A. Saber ◽  
Khalid M. Ghoneem ◽  
Elsayed E. Hafez ◽  
Amira A. Ibrahim
Keyword(s):  
Citric Acid ◽  
Plant Growth ◽  
Organic Acid ◽  
Wilt Disease ◽  
Growth And Yield ◽  
Total Phenolic ◽  
Growth Promoters ◽  
Chlorophyll Pigments

Presently, the bioprocessing of agricultural residues to various bioactive compounds is of great concern, with the potential to be used as plant growth promoters and as a reductive of various diseases. Lycopersiconesculentum, one of the most consumed crops in the human diet, is attacked by Fusarium wilt disease, so the main aim is to biocontrol the pathogen. Several fungal species were isolated from decayed maize stover (MS). Trichodermaasperellum was chosen based on its organic acid productivity and was molecularly identified (GenBank accession number is MW195019). Citric acid (CA) was the major detected organic acid by HPLC. In vitro, CA of T.asperellum at 75% completely repressed the growth of Fusariumoxysporum f. sp. lycopersici (FOL). In vivo, soaking tomato seeds in CA enhanced the seed germination and vigor index. T. asperellum and/or its CA suppressed the wilt disease caused by FOL compared to control. There was a proportional increment of plant growth and yield, as well as improvements in the biochemical parameters (chlorophyll pigments, total phenolic contents and peroxidase, and polyphenol oxidase activities), suggesting targeting both the bioconversion of MS into CA and biological control of FOL.

CHANGES IN THE THERMAL STABILITY AND ACIDIC CHARACTERISTICS OF HYDROXY-Al-MONTMORILLONITE COMPLEXES FORMED IN THE PRESENCE OF CITRIC ACID

1985 ◽  
Vol 65 (3) ◽  
pp. 519-522 ◽  
Author(s):  
TEE BOON GOH ◽  
P. M. HUANG
Keyword(s):  
Thermal Stability ◽  
Citric Acid ◽  
Organic Carbon ◽  
Organic Acid ◽  
Key Words ◽  
Titratable Acidity ◽  
Structural Water ◽  
Molar Ratios ◽  
Gradual Loss

The thermal stability and acidic characteristics of Al interlayered montmorillonite were affected by citric acid which was present during its formation. Perturbation to the formation of Al interlayers by citric acid resulted in more gradual loss of their structural water in the 430 °C to 520 °C region at initial citric acid/Al molar ratios of 0.1 and 0.5. The data clearly reveal that, besides hydroxy-Al polymers, hydroxy-Al-citrate complexes adsorbed on the surfaces of montmorillonite very substantially contribute to the total and third buffer range titratable acidity of the clay. Key words: Hydroxy-Al-citrate interlayers, smectite, organic acid, DTA, third buffer range, organic carbon

Effects of Additives in KOH Based Electrolytes on Cu ECMP

2007 ◽  
Vol 991 ◽  
Author(s):  
Tae-Young Kwon ◽  
In-Kwon Kim ◽  
Jin-Goo Park
Keyword(s):  
Citric Acid ◽  
Applied Voltage ◽  
Counter Electrode ◽  
Corrosion Potential ◽  
Removal Rate ◽  
Chemical Mechanical Planarization ◽  
Corrosion Current ◽  
Dynamic State ◽  
Static State ◽  
Potentiodynamic Curves

ABSTRACTThe purpose of this study was to characterize KOH based electrolytes and effects of additives on electro-chemical mechanical planarization. The electrochemical mechanical polisher was made to measure the potentiodynamic curve and removal rate of Cu. The potentiodynamic curves were measured in static and dynamic states in investigated electrolytes using a potentiostat. Cu disk of 2 inch was used as a working electrode and Pt electroplated platen was used as a counter electrode. KOH was used as the electrolyte. H2O2 and citric acid were used as additives for the ECMP of Cu. In static and dynamic potentiodynamic measurements, the corrosion potential decreased and corrosion current increased as a function of KOH concentration. In dynamic state, different potentiodynamic curve was obtained when compared to the static state. The current density did not decrease in passivation region by mechanical polishing effect. The static etch and removal rate were measured as function of KOH concentration and applied voltage. In ECMP system, polishing was performed at 30 rpm and 1 psi. The removal rate was about 60 nm/min at 0.3 V when 5 wt% KOH was used. Also, the effect of additive was investigated in KOH based electrolyte on removal rates. As a result, The removal rate was increased to 350 nm/min when 5wt% KOH, 5vol% H2O2, 0.3 M citric acid were used.

The Effect of Organic Matter and Organic Acid on the Chromium Release in Sediment

2014 ◽  
Vol 1081 ◽  
pp. 88-92
Author(s):  
Hui Liu ◽  
Jiu Lan Dai
Keyword(s):  
Heavy Metals ◽  
Organic Matter ◽  
Citric Acid ◽  
Organic Acid ◽  
Ethylene Diamine Tetraacetic Acid ◽  
Soluble Starch ◽  
Optimal Dosage ◽  
Tetraacetic Acid ◽  
Adsorption Time ◽  
Chromium Release

Effect of organic matter and organic acid on the heavy metals, especially, chromium (Cr) release in the sediment was researched. Glucose and soluble organic starch was used as organic matter, as well, citric acid and ethylene diamine tetraacetic acid (EDTA) were simulated as organic acid. The results showed that best adsorption time of glucose on Cr was 5h, the optimal dosage was 0.1g g-1; best adsorption time of organic soluble starch was 4h, and the optimum adding amount of 0.08g/g; best adsorption time of citric acid was 5h, the best concentration 0.005mol g-1; optimal adsorption time of organic acid EDTA was 3h, the optimum adding amount of 0.12g g-1. Glucose, soluble starch and citric acid significantly effected on the release of Cr in the sediment, however, influence of EDTA on the release of Cr was not so evident.

scholarly journals Size-Controlled Preparation of Gold Nanoparticles Deposited on Surface-Fibrillated Cellulose obtained by Citric Acid-Modification

2020 ◽  
Author(s):  
Chutimasakul Threeraphat ◽  
Yuta Uetake ◽  
Jonggol Tantirungrotechai ◽  
Taka-Aki Asoh ◽  
Hiroshi Uyama ◽  
...  
Keyword(s):  
Particle Size ◽  
Citric Acid ◽  
Aerobic Oxidation ◽  
Functional Materials ◽  
Deposition Efficiency ◽  
Acid Modification ◽  
Au Nps ◽  
Size Growth ◽  
Controlled Preparation ◽  
Hydroxy Groups

<p>Cellulose-based functional materials have gained immense interest due to its low density, hydrophilicity, chirality, and degradability. So far, a facile and scalable preparation of fibrillated cellulose by treating the hydroxy groups of cellulose with citric acid (F-CAC) have been developed, and applied as a reinforcing filler for polypropylene composite. Herein, a size-selective preparation of Au nanoparticles (NPs) stabilized by F-CAC is described. By modifying the conditions of trans-deposition method, established in our group previously, a transfer of Au NPs from poly(<i>N</i>-vinyl-2-pyrrolidone) (PVP) to F-CAC proceeded up to 96% transfer efficiency with retaining its cluster sizes in EtOH. Meanwhile, the deposition efficiency drastically decreased in the case of non-modified cellulose, showing the significance of citric acid-modification. A shift of binding energy at Au 4f core level X-ray photoelectron microscopy (XPS) from 82.0 eV to 83.3 eV indicated that the NPs were stabilized on a F-CAC surface rather than by PVP matrix. The reproducible particle size growth was observed when 2-propanol was used as a solvent instead of EtOH, expanding the range of the available particle size with simple manipulation. The thus-obtained Au:F-CAC nanocatalysts exhibited a catalytic activity toward an aerobic oxidation of 1-indonol in toluene to yield 1-indanone quantitatively, and were recyclable at least 6 times, illustrating high tolerance against organic solvents.</p>

Citric acid modified Ni3P as a catalyst for aqueous phase reforming and hydrogenolysis of glycerol to 1,2-PDO

2021 ◽  
Author(s):  
Tianyu Hu ◽  
Zhiquan Yu ◽  
Shan Liu ◽  
Bingyu Liu ◽  
Zhichao Sun ◽  
...  
Keyword(s):  
Particle Size ◽  
Citric Acid ◽  
Aqueous Phase ◽  
Small Particle ◽  
Small Particle Size ◽  
Temperature Programmed Reduction ◽  
Aqueous Phase Reforming ◽  
Temperature Programmed ◽  
Co Precipitation

Citric acid (CA) modified Ni3P catalysts with small particle size were prepared by H2 temperature-programmed reduction (H2-TPR) of the precursors, which were prepared by co-precipitation with Ni(NO3)2·6H2O and (NH4)2HPO4, using...

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