Coagulation performance of cucurbit[8]uril for the removal of azo dyes: effect of solution chemistry and coagulant dose

2018 ◽  
Vol 78 (2) ◽  
pp. 415-423 ◽  
Author(s):  
Wendong Wang ◽  
Zhiwen Chen ◽  
Kun Wu ◽  
Zongkuan Liu ◽  
Shengjiong Yang ◽  
...  
Keyword(s):  
Solution Chemistry ◽  
Color Removal ◽  
Dye Wastewater ◽  
Removal Rates ◽  
Molecular Weights ◽  
Coagulation Performance ◽  
Wide Ph Range ◽  
Ph Range ◽  
Significant Attention ◽  
Cr Removal

Abstract Dye wastewater has attracted significant attention because of its wide pH range and high content of color. In this work, the coagulation performances of cucurbit[8]uril for the removal of color from acid red 1 (AR1), orange II (OII), and Congo red (CR) dye wastewaters were investigated. Experimental results showed that color removal rates of greater than 95% for AR1, OII and CR were achieved at pH 6.0, when the dosage of cucurbit[8]uril was 1.51, 3.01 and 0.38 mmol·L−1, respectively. Under identical conditions, the color removal efficiencies of AR1 and CR were higher than OII, due to the larger molecular weights and more active hydroxyl and amino groups. Moreover, steady increases in AR1, OII and CR removal rates were recorded with increasing ionic strength. Such increases may be related to the reduction in thickness of the surface solvent membrane surrounding the dye colloids at high ionic strengths. Furthermore, Fourier transform infrared spectra demonstrated that no new bonds or functional groups were formed during coagulation, which indicates that the removal of AR1, OII and CR was primarily a physical process. The hydrogen bonds and inclusion complexes formed between cucurbit[8]uril and AR1, OII and CR contributed to the removal of color in coagulation predominantly.

scholarly journals Tuning the Properties of High Molecular Weight Chitosans to Develop Full Water Solubility Within a Wide pH Range

2020 ◽  
Author(s):  
Anderson Fiamingo ◽  
Sergio Paulo Campana Filho ◽  
Osvaldo Novais Oliveira Junior
Keyword(s):  
Molecular Weight ◽  
Biomedical Applications ◽  
Random Distribution ◽  
Water Solubility ◽  
Aqueous Media ◽  
Degree Of Polymerization ◽  
Molecular Weights ◽  
H Nmr ◽  
Wide Ph Range ◽  
Ph Range

<p>The preparation of chitosans soluble in physiological conditions has been sought for years, but so far solubility in non-acidic aqueous media has only been achieved at the expense of lowering chitosan molecular weight. In this work, we applied the multistep ultrasound-assisted deacetylation process (USAD process) to β-chitin and obtained extensively deacetylated chitosans with high molecular weights (Mw ≥ 1,000,000 g mol<sup>-1</sup>). The homogeneous <i>N</i>-acetylation of a chitosan sample resulting from three consecutive USAD procedures allowed us to produce chitosans with a high weight average degree of polymerization (DPw ≈ 6,000) and tunable degrees of acetylation (DA from 5 to 80%). <i>N</i>-acetylation was carried out under mild conditions to minimize depolymerization, while preserving a predominantly random distribution of 2-amino-2-deoxy-D-glucopyanose (<i>GlcN</i>) and 2-acetamido-2-deoxy-D-glucopyanose (<i>GlcNAc</i>) units. This close to random distribution, inferred with deconvolution of nuclear magnetic resonance (<sup>1</sup>H NMR) spectra, is considered as responsible for the solubility within a wide pH range. Two of the highly <i>N</i>-acetylated chitosans (DA ≈ 60 % and ≈ 70 %) exhibited full water solubility even at neutral pH, which can expand the biomedical applications of chitosans. </p>

scholarly journals Purification and Characterization of Strong Simultaneous Enzyme Production of Protease and α-Amylase from an Extremophile-Bacillus sp. FW2 and Its Possibility in Food Waste Degradation

Fermentation ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 12
Author(s):  
Van Hong Thi Pham ◽  
Jaisoo Kim ◽  
Jeahong Shim ◽  
Soonwoong Chang ◽  
Woojin Chung
Keyword(s):  
Food Waste ◽  
Environmental Conditions ◽  
Enzyme Production ◽  
Molecular Weights ◽  
Sds Page ◽  
Metabolic Products ◽  
Wide Ph Range ◽  
Waste Degradation ◽  
Ph Range

Microbial enzymes such as protease and amylase are valuable enzymes with various applications, widely investigated for their applications in degradation of organic waste, biofuel industries, agricultural, pharmaceuticals, chemistry, and biotechnology. In particular, extremophiles play an important role in biorefinery due to their novel metabolic products such as high value catalytic enzymes that are active even under harsh environmental conditions. Due to their potentials and very broad activities, this study isolated, investigated, and characterized the protease- and amylase-producing bacterial strain FW2 that was isolated from food waste. Strain FW2 belongs to the genus Bacillus and was found to be closest to Bacillus amyloliquefaciens DSM 7T with a similarity of 99.86%. This strain was able to degrade organic compounds at temperatures from −6 °C to 75 °C (but weak at 80 °C) under a wide pH range (4.5–12) and high-salinity conditions up to 35% NaCl. Maximum enzyme production was obtained at 1200 ± 23.4 U/mL for protease and 2400 ± 45.8 U/mL for amylase for 4 days at pH 7–7.5, 40–45 °C, and 0–10% NaCl. SDS-PAGE analysis showed that the molecular weights of purified protease were 28 kDa and 44 kDa, corresponding to alkaline protease (AprM) and neutral protease (NprM), respectively, and molecular weight of α-amylase was 55 kDa. Degradation food waste was determined after 15 days, observing a 69% of volume decrease. A potential commercial extremozyme-producing bacteria such as strain FW2 may be a promising contributor to waste degradation under extreme environmental conditions.

scholarly journals Tuning the Properties of High Molecular Weight Chitosans to Develop Full Water Solubility Within a Wide pH Range

2020 ◽  
Author(s):  
Anderson Fiamingo ◽  
Sergio Paulo Campana Filho ◽  
Osvaldo Novais Oliveira Junior
Keyword(s):  
Molecular Weight ◽  
Biomedical Applications ◽  
Random Distribution ◽  
Water Solubility ◽  
Aqueous Media ◽  
Degree Of Polymerization ◽  
Molecular Weights ◽  
H Nmr ◽  
Wide Ph Range ◽  
Ph Range

<p>The preparation of chitosans soluble in physiological conditions has been sought for years, but so far solubility in non-acidic aqueous media has only been achieved at the expense of lowering chitosan molecular weight. In this work, we applied the multistep ultrasound-assisted deacetylation process (USAD process) to β-chitin and obtained extensively deacetylated chitosans with high molecular weights (Mw ≥ 1,000,000 g mol<sup>-1</sup>). The homogeneous <i>N</i>-acetylation of a chitosan sample resulting from three consecutive USAD procedures allowed us to produce chitosans with a high weight average degree of polymerization (DPw ≈ 6,000) and tunable degrees of acetylation (DA from 5 to 80%). <i>N</i>-acetylation was carried out under mild conditions to minimize depolymerization, while preserving a predominantly random distribution of 2-amino-2-deoxy-D-glucopyanose (<i>GlcN</i>) and 2-acetamido-2-deoxy-D-glucopyanose (<i>GlcNAc</i>) units. This close to random distribution, inferred with deconvolution of nuclear magnetic resonance (<sup>1</sup>H NMR) spectra, is considered as responsible for the solubility within a wide pH range. Two of the highly <i>N</i>-acetylated chitosans (DA ≈ 60 % and ≈ 70 %) exhibited full water solubility even at neutral pH, which can expand the biomedical applications of chitosans. </p>

Color Removal of Reactive Brilliant Blue KN-R Simulated Dye Wastewater by Using Novel Flocculants

2012 ◽  
Vol 610-613 ◽  
pp. 1939-1942
Author(s):  
Ji Zhou Li ◽  
Xu Yin Yuan ◽  
Ming Tian ◽  
Hao Ran Ji ◽  
Wan Jiang
Keyword(s):  
Removal Efficiency ◽  
Color Removal ◽  
Brilliant Blue ◽  
Solution Temperature ◽  
Optimal Dosage ◽  
Dye Wastewater ◽  
Decolorization Efficiency ◽  
Initial Ph ◽  
Simulated Wastewater ◽  
Ph Range

In this study, five novel flocculants, QTRY-02, DC-491, Fennofix K97, BWD-01 and MD-03 were chosen to treat Reactive Brilliant Blue KN-R simulated wastewater by jar tests. The effect of flocculant dosage, initial pH, solution temperature of simulated dye wastewater and sedimentaion time on the color removal was examined respectively. The maximum color removal efficiency of KN-R was over 82% after 20 minutes of sedimentation and the optimal dosage was 150mg/L for all flocculants. In the pH range from 3 to 11, small changes in the color removal efficiency for QTRY-02. While for BWD-01, the efficiency increased from 67.3% to 88.3%. For both QTRY-02 and MD-04, decolorization efficiency increased as the solution temperature increased from 10°C to 50°C and the same result appeared when prolonging the sedimentation time from 1 to 12 hours.

Polarographic and spectrophotometric behaviour of some N-p-phenyl substituted benzamidines

1991 ◽  
Vol 56 (12) ◽  
pp. 2791-2799 ◽  
Author(s):  
Juan A. Squella ◽  
Luis J. Nuñez-Vergara ◽  
Hernan Rodríguez ◽  
Amelia Márquez ◽  
Jose M. Rodríguez-Mellado ◽  
...  
Keyword(s):  
Spectrophotometric Study ◽  
Absorption Bands ◽  
Electrochemical Parameters ◽  
Wide Ph Range ◽  
Group A ◽  
Substituent Constants ◽  
Ph Range ◽  
The Waves

Five N-p-phenyl substituted benzamidines were studied by DC and DP polarography in a wide pH range. Coulometric results show that the overall processes are four-electron reductions. Logarithmic analysis of the waves indicate that the process are irreversible. The influence of the pH on the polarographic parameters was also studied. A UV spectrophotometric study was performed in the pH range 2-13. In basic media some variations in the absorption bands were observed due to the dissociation of the amidine group. A determination of the pK values was made by deconvolution of the spectra. Correlations of both the electrochemical parameters and spectrophotometric pK values with the Hammett substituent constants were obtained.

High degradation efficiency of sulfamethazine with the dual-reaction-center Fe-Mn-SiO2 Fenton-like nanocatalyst in a wide pH range

2021 ◽  
Author(s):  
Manoj Kumar Panjwani ◽  
Qing Wang ◽  
Yueming Ma ◽  
Yuxuan Lin ◽  
Feng Xiao ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Reaction Center ◽  
Degradation Efficiency ◽  
Heterogeneous Fenton ◽  
Wide Ph Range ◽  
Ph Range

The development of a heterogeneous Fenton-like catalyst, possessing high degradation efficiency in a wide pH range, is crucial for wastewater treatment. The Fe-Mn-SiO2 catalyst was designed, and prepared by a...

scholarly journals Defect-Rich Heterogeneous MoS2/rGO/NiS Nanocomposite for Efficient pH-Universal Hydrogen Evolution

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 662 ◽  
Author(s):  
Guangsheng Liu ◽  
Kunyapat Thummavichai ◽  
Xuefeng Lv ◽  
Wenting Chen ◽  
Tingjun Lin ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Active Sites ◽  
Reduced Graphene ◽  
Heterogeneous Interfaces ◽  
Wide Ph Range ◽  
Ph Range ◽  
A Current ◽  
Poor Stability

Molybdenum disulfide (MoS2) has been universally demonstrated to be an effective electrocatalytic catalyst for hydrogen evolution reaction (HER). However, the low conductivity, few active sites and poor stability of MoS2-based electrocatalysts hinder its hydrogen evolution performance in a wide pH range. The introduction of other metal phases and carbon materials can create rich interfaces and defects to enhance the activity and stability of the catalyst. Herein, a new defect-rich heterogeneous ternary nanocomposite consisted of MoS2, NiS and reduced graphene oxide (rGO) are synthesized using ultrathin αNi(OH)2 nanowires as the nickel source. The MoS2/rGO/NiS-5 of optimal formulation in 0.5 M H2SO4, 1.0 M KOH and 1.0 M PBS only requires 152, 169 and 209 mV of overpotential to achieve a current density of 10 mA cm−2 (denoted as η10), respectively. The excellent HER performance of the MoS2/rGO/NiS-5 electrocatalyst can be ascribed to the synergistic effect of abundant heterogeneous interfaces in MoS2/rGO/NiS, expanded interlayer spacings, and the addition of high conductivity graphene oxide. The method reported here can provide a new idea for catalyst with Ni-Mo heterojunction, pH-universal and inexpensive hydrogen evolution reaction electrocatalyst.

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