scholarly journals Sustainable Development of Magnetic Chitosan Core–Shell Network for the Removal of Organic Dyes from Aqueous Solutions

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7701
Author(s):  
Karthik Rathinam ◽  
Xinwei Kou ◽  
Ralph Hobby ◽  
Stefan Panglisch
Keyword(s):  
Electrostatic Interactions ◽  
Dye Removal ◽  
Adsorption Process ◽  
Organic Dyes ◽  
Core Shell ◽  
Order Kinetic ◽  
Alizarin Red ◽  
Anthraquinone Dye ◽  
Magnetic Chitosan ◽  
Repulsive Forces

The wide use of alizarin red S (ARS), a typical anthraquinone dye, has led to its continued accumulation in the aquatic environment, which causes mutagenic and carcinogenic effects on organisms. Therefore, this study focused on the removal of ARS dye by adsorption onto a magnetic chitosan core–shell network (MCN). The successful synthesis of the MCN was confirmed by ATR-FTIR, SEM, and EDX analysis. The influence of several parameters on the removal of ARS dye by the MCN revealed that the adsorption process reached equilibrium after 60 min, pH played a major role, and electrostatic interactions dominated for the ARS dye removal under acidic conditions. The adsorption data were described well by the Langmuir isotherm and a pseudo-second order kinetic model. In addition to the preferable adsorption of hydrophobic dissolved organic matter (DOM) fractions onto the MCN, the electrostatic repulsive forces between the previously adsorbed DOM onto MCN and ARS dye resulted in lower ARS dye removal. Furthermore, the MCN could easily be regenerated and reused for up to at least five cycles with more than 70% of its original efficiency. Most importantly, the spent MCN was pyrolytically converted into N-doped magnetic carbon and used as an adsorbent for various dyes, thus establishing a waste-free adsorption process.

scholarly journals Bathurst Burr (Xanthium spinosum) Powder—A New Natural Effective Adsorbent for Crystal Violet Dye Removal from Synthetic Wastewaters

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5861
Author(s):  
Giannin Mosoarca ◽  
Cosmin Vancea ◽  
Simona Popa ◽  
Sorina Boran
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Taguchi Method ◽  
Size Distribution ◽  
Crystal Violet ◽  
Dye Removal ◽  
Adsorption Process ◽  
Distribution Analysis ◽  
Order Kinetic ◽  
Crystal Violet Dye

A new natural adsorbent material, Bathurst burr powder, was used to remove crystal violet dye from synthetic wastewaters. Particle size distribution and SEM and FTIR analyses were performed to characterize it. The effect of the operational adsorption process parameters (pH, ionic strength, initial dye concentration, adsorbent dose, contact time, temperature) onto the adsorption process was evaluated in a batch system. Equilibrium, kinetic, and thermodynamic studies were performed in order to understand the adsorption process. Taguchi method and ANOVA test were used to optimize the dye adsorption conditions and to establish the percentage contribution of each factor, respectively. The accuracy of the Taguchi prediction method was analyzed by correlating the predicted dye removal efficiency with the experimentally determined one. The particle size distribution analysis showed that 82.15% of the adsorbent particles have an average size below 0.5 mm. The adsorption process followed the Langmuir isotherm and pseudo-second order kinetic model. Maximum adsorption capacity value (164.10 mg·g−1) was higher compared to many similar adsorbents. The process was endothermic, spontaneous, and favorably involving a physisorption mechanism. The Taguchi method showed that the most influential controllable factor was pH (65% contribution in adsorption efficiency) and the data analysis indicates a very good accuracy of the experimental design (R2 = 0.994). The obtained results demonstrated that Bathurst burr powder can be used as a cheap and efficient adsorbent for crystal violet dye removal from aqueous solution.

scholarly journals Removal and Adsorption Mechanism of Tetracycline Using Manganese-modified Cotton Straw Biochar in an Aqueous Solution

2021 ◽  
Author(s):  
Xiao Liu ◽  
Shaoyang Shi ◽  
Xuefei Hu ◽  
Tao Sun ◽  
Juanxiang Zhang ◽  
...  
Keyword(s):  
Rural Areas ◽  
Electrostatic Interactions ◽  
Adsorption Process ◽  
Solution Concentration ◽  
Order Kinetic ◽  
Adsorption Effect ◽  
Adsorption Mechanisms ◽  
Aqueous Environments ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Abstract Farming in China’s rural areas leads to antibiotic pollution in waterbodies making it a grave issue. Cotton straw biochar (CSBC) was prepared by oxygen-limited pyrolysis at 400 °C (CSBC400) and 600 °C (CSBC600); and Mn-modified CSBC (MCSBC) was produced by the KMnO4 wrapping method for tetracycline (TC) removal from aqueous solutions. The effects of temperature, initial solution concentration, pH, ion type, and ionic strength on TC adsorption were investigated. The adsorption process of the biochars achieved an equilibrium state after 360 min, and the highest equilibrium adsorption amount (13.254 mg/g) was found for MCSBC. The kinetic adsorption process, which was dominated by chemisorption, was well-described by the pseudo-second-order kinetic model. The adsorption was a non-homogeneous heat absorption process, and the adsorption isotherm data fitting was compatible with the Freundlich model. A better adsorption effect of MCSBC was observed when the pH was < 4. Monovalent cations (Na+, K+, NH4+, and Ca2+) had a facilitative effect on the adsorption process. The adsorption mechanisms of TC by MCSBC included pore diffusion, H bonding, electrostatic interactions, and π–π accumulation. Therefore, MCSBC has a good adsorption capacity for TC and can be used for the treatment of TC-based pollutants in aqueous environments.

Selective Adsorption and Separation of Organic Dyes by Poly(acrylic acid) Hydrogels Formed with Spherical Polymer Brushes and Chitosan

2018 ◽  
Vol 71 (11) ◽  
pp. 846 ◽  
Author(s):  
Rui Zhang ◽  
Hongwei Peng ◽  
Tianxu Zhou ◽  
Min Li ◽  
Xuhong Guo ◽  
...  
Keyword(s):  
Acrylic Acid ◽  
Polymer Brushes ◽  
Electrostatic Interactions ◽  
Separation Efficiency ◽  
Organic Dyes ◽  
Selective Adsorption ◽  
Cationic Dyes ◽  
Order Kinetic ◽  
Double Network ◽  
Poly Acrylic Acid

Direct discharge of industry organic dyes has caused serious environmental pollution. In this study, a series of double network poly(acrylic acid) (PAA) hydrogels were fabricated with spherical polymer brushes (SPBs) and chitosan (CS) as crosslinker. Neutral spherical polyelectrolyte brushes of polystyrene–poly-N-isopropylacrylamide (PNIPAM@PS) in which poly(N-isopropylacrylamide) (PNIPAM) arms were grafted on polystyrene (PS) nanospheres, were employed as macro-crosslinkers. The innumerable hydrogen bonds both between the highly entangled PAA chains and between PNIPAM and the PAA chains composed the first network of the hydrogels. The electrostatic interactions between CS and the PAA chains formed the second network of the hydrogels. These double network hydrogels, named PNIPAM@PS/CS/PAA, achieve good compressive performance and a low swell ratio because of their compact structure through plentiful hydrogen bonding and electrostatic interactions. The hydrogel could absorb cationic dyes from water with high separation efficiency and selectivity due to the electrostatic interaction between the carboxy groups and dye molecules. The adsorption process fitted a pseudo-second-order kinetic model and Langmuir isotherm model very well. Moreover, the hydrogel can separate cationic dyes from mixed dye solutions through electrostatic interactions. After being loaded with silver nanoparticles, the obtained silver@hydrogel exhibited a good capacity for the photocatalytic degradation towards different dyes. The hydrogels are promising for dye-containing wastewater treatment.

scholarly journals Adsorption of Pb2+ from Aqueous Solutions Using Novel Functionalized Corncobs via Atom Transfer Radical Polymerization

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1715 ◽  
Author(s):  
Shanglong Chen ◽  
Wei Zhao
Keyword(s):  
Aqueous Solutions ◽  
Atom Transfer Radical Polymerization ◽  
Radical Polymerization ◽  
Electrostatic Interactions ◽  
Adsorption Process ◽  
Atom Transfer ◽  
Order Kinetic ◽  
Solution Ph ◽  
Carboxylate Groups ◽  
Working Solution

The present study developed novel functionalized corncobs introducing brushes with dense and active carboxyl groups (–COOH), named MC-g-PAA, for the highly efficient adsorption of Pb2+ from aqueous solutions. MC-g-PAA were synthesized via atom transfer radical polymerization (ATRP) and characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The amount of Pb2+ adsorbed on MC-g-PAA by hydrolysis with t-BuOK was 2.28 times greater than that with NaOH, attributed to the larger steric effect of t-BuOK, which reduced the hydrolysis of the bromo-ester groups. The influence of different parameters including the solid/liquid ratio, working solution pH, sorption temperature, and initial concentration and sorption time on the adsorption of Pb2+ were investigated in detail in batch experiments. Thermodynamic studies have shown that the adsorption process was spontaneous, endothermic, and accompanied by an increase in randomness. A better fit for the isotherm data was obtained using the Langmuir model than for the other four models and the maximum amount ( q max ) of Pb2+ adsorbed on MC-g-PAA was 342.47 mg/g, which is 21.11 times greater when compared with that of pristine corncobs (16.22 mg/g). The adsorption of Pb2+ on MC-g-PAA was very fast and followed the pseudo-second-order kinetic equation with a correlation coefficient of 0.99999. This monolayer adsorption process was dominated by chemical adsorption, and may proceed according to complexation and electrostatic interactions between Pb2+ and the carboxylate groups. This study indicated that MC-g-PAA could be successfully used as an adsorbent for the removal of Pb2+ from aqueous solutions due to its excellent efficiency.

scholarly journals Castor Leaves-Based Biochar for Adsorption of Safranin from Textile Wastewater

2021 ◽  
Vol 13 (12) ◽  
pp. 6926
Author(s):  
Muhammad Suleman ◽  
Muhammad Zafar ◽  
Ashfaq Ahmed ◽  
Muhammad Usman Rashid ◽  
Sadiq Hussain ◽  
...  
Keyword(s):  
Contact Time ◽  
Dye Removal ◽  
Adsorption Process ◽  
Research Work ◽  
Freundlich Isotherm ◽  
Textile Wastewater ◽  
Isotherm Model ◽  
Textile Dye ◽  
Order Kinetic ◽  
Surface Areas

The prospect of synthesizing biochar from agricultural wastes or by-products to utilize them as a promising adsorbent material is increasingly gaining attention. This research work focuses on synthesizing biochar from castor biomass (CBM) and evaluating its potential as an adsorbent material. Castor biomass-based biochar (CBCs) prepared by the slow pyrolysis process at different temperatures (CBC400 °C, CBC500 °C, and CBC600 °C for 1 h) was investigated for the adsorption of textile dye effluents (safranin). The pyrolysis temperature played a key role in enhancing the morphology, and the crystallinity of the biochar which are beneficial for the uptake of safranin. The CBC600 adsorbent showed a higher safranin dye removal (99.60%) and adsorption capacity (4.98 mg/g) than CBC500 (90.50% and 4.52 mg/g), CBC400 (83.90% and 4.20 mg/g), and castor biomass (CBM) (64.40% and 3.22 mg/g). Adsorption data fitted better to the Langmuir isotherm model than to the Freundlich isotherm model. The kinetics of the adsorption process was described well using the pseudo-second-order kinetic model. The study on the effect of the contact time for the adsorption process indicated that for CBC600, 80% dye removal occurred in the first 15 min of the contact time. After three regeneration cycles, CBC600 exhibited the highest dye removal efficiency (64.10%), highlighting the enhanced reusability of CBCs. The crystalline patterns, functional binding sites, and surface areas of the prepared CBCs (CBC400, CBC500, CBC600) were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and Brunauer–Emmett–Teller surface area measurements, respectively.

scholarly journals Removal of Methylene Blue Dye using Carbon Derived from Bulb of Zephyranthes citrina: Adsorption and Kinetic Studies

2020 ◽  
Vol 32 (6) ◽  
pp. 1352-1360
Author(s):  
J. Prakash ◽  
S. Vedanayaki ◽  
K. Karthick
Keyword(s):  
Methylene Blue ◽  
Adsorption Process ◽  
Organic Dyes ◽  
Kinetic Studies ◽  
Batch Process ◽  
Blue Dye ◽  
Aqueous Sample ◽  
Order Kinetic ◽  
Methylene Blue Dye ◽  
First Order

The studies open up an innovative approach and investigate porous, efficient raw carbon from Zephyranthes citrina bulb, which was used as an adsorbent to remove organic dyes. The well-dried and finely powdered Zephyranthes citrina bulb was carbonized at 900 ºC. The carbonized crude Z. citrina sample was characterized by FT-IR, UV-visible, scanning electron microscopy (SEM), BET, X-ray diffraction (XRD) techniques and their adsorption potential to remove the basic methylene blue dye from an aqueous sample. Adsorption studies comprise both adsorption isotherm and kinetic methods. The processes were carried out with diverse adsorbate concentrations and adsorbent quantities at various time intervals in the batch process. Kinetic models of Lagergren first order, pseudo-second order and intra particle diffusion were used to assess the kinetics and adsorption mechanism. The results revealed that the adsorption process follows the first order kinetic model of Lagergren. The BET isotherm model confirmed that it has an excellent adsorption capacity in an adsorption process. Based on the results obtained, the maximum removal (81%) of dye was achieved in a solution containing 50 mg of 50 mL dye at 3 h for methylene blue. The results indicated that the bulb of Zephyranthes citrina carbon is a proficient adsorption material and is also used as a cost effective alternative that can adsorb dye from an aqueous solution without activation treatment.

Removal of caffeine by oxidized biochar

2020 ◽  
Author(s):  
Ioannis Anastopoulos ◽  
Ioannis Pashalidis ◽  
Artis Robalds
Keyword(s):  
Contact Time ◽  
Electrostatic Interactions ◽  
Plant Biomass ◽  
Freundlich Isotherm ◽  
Outer Sphere ◽  
Initial Step ◽  
Order Kinetic ◽  
Surface Complexes ◽  
Order Kinetic Model ◽  
Repulsive Forces

&lt;p&gt;Oxidized biochar from plant biomass (OBPM) was used to remove caffeine (CF) from aqueous solutions. Among examined parameters that affect adsorption, pH was found to play the most important role.&amp;#160;By increasing&amp;#160;the initial&amp;#160;pH&amp;#160;from 2 to 4, the&amp;#160;adsorption capacity&amp;#160;of CF was increased, whereas for pH above 4, a decline of the adsorption efficiency was noticed. The effect of contact time was also investigated in the range of 1 &amp;#8211; 150 minutes and results indicated that the adsorption process consists of two steps. The initial step was relatively fast most probably, because a large number of adsorption surface sites was available, and with proceeding contact time the adsorption rate declined. The latter could be attributed to the decreasing number of vacant sites and to the development of repulsive forces between the free CF molecules and the occupied OBPM surface. The experimental data were best fitted by the pseudo-second order kinetic, compared to pseudo-first order kinetic model and the Freundlich isotherm model better fitted the data. The raise of temperature from 25 to 50 &amp;#176;C affected negatively the CF removal, indicating the exothermicity of the adsorption. Finally, FTIR spectroscopic data and investigations on the effect of ionic strength indicated that the adsorption mechanism is mainly based on electrostatic interactions and the formation of outer sphere surface complexes.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;&amp;#160;&lt;/strong&gt;&lt;/p&gt;

scholarly journals Pillar[6]arene-based supramolecular polymeric materials constructed via electrostatic interactions for rapid and efficient organic dye removal from water

2021 ◽  
Author(s):  
Yong Yao ◽  
Xin Yan ◽  
Youyou Huang ◽  
Moupan Cen ◽  
Jin Wang ◽  
...  
Keyword(s):  
Electrostatic Interactions ◽  
Dye Removal ◽  
Organic Dyes ◽  
Polymeric Materials ◽  
Organic Dye

A pillar[6]arene-based polymeric materials was constructed from electrostatic interactions efficiently, which can further apply in removing organic dyes from water.

scholarly journals Layer-by-Layer Assembly and Electrochemical Study of Alizarin Red S-Based Thin Films

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 165 ◽  
Author(s):  
Wei Ma ◽  
Yanpu Zhang ◽  
Fei Li ◽  
Donghui Kou ◽  
Jodie Lutkenhaus
Keyword(s):  
Electrochemical Properties ◽  
Color Change ◽  
Organic Dyes ◽  
Co Adsorption ◽  
Growth Patterns ◽  
Alizarin Red S ◽  
Layer By Layer ◽  
Ethylene Imine ◽  
Alizarin Red ◽  
Anthraquinone Dye

Electroactive organic dyes incorporated in layer-by-layer (LbL) assemblies are of great interest for a variety of applications. In this paper, Alizarin Red S (ARS), an electroactive anthraquinone dye, is employed to construct LbL (BPEI/ARS)n films with branched poly(ethylene imine) (BPEI) as the complementary polymer. Unconventional LbL methods, including co-adsorption of ARS and poly(4-styrene sulfonate) (PSS) with BPEI to assemble (BPEI/(ARS+PSS))n, as well as pre-complexation of ARS with BPEI and further assembly with PSS to fabricate ((BPEI+ARS)/PSS)n, are designed for investigation and comparison. Film growth patterns, UV–Vis spectra and surface morphology of the three types of LbL assemblies are measured and compared to reveal the formation mechanism of the LbL films. Electrochemical properties including cyclic voltammetry and spectroelectrochemistry of (BPEI/ARS)120, (BPEI/(ARS+PSS))120 and ((BPEI+ARS)/PSS)120 films are studied, and the results show a slight color change due to the redox reaction of ARS. ((BPEI+ARS)/PSS)120 shows the best stability among the three samples. It is concluded that the manner of dye- incorporation has a great effect on the electrochemical properties of the resultant films.

Surface interaction of sweet potato peels (Ipomoea batata) with Cd(II) and Pb(II) ions in aqueous medium

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Aqueous Medium ◽  
Sweet Potato ◽  
Adsorption Process ◽  
Low Cost ◽  
Correlation Coefficients ◽  
Order Kinetic ◽  
Thermodynamic Evaluation ◽  
Dissociative Mechanism ◽  
Pseudo Second Order ◽  
Potato Peels

The removal of Cd(II) and Pb(II) ions from aqueous medium was studied using potato peels biomass. The adsorption process was evaluated using Atomic Absorption Spectrophotometer (AAS). The Vibrational band of the potato peels was studied using Fourier Transform Infrared Spectroscopy (FTIR). The adsorption process was carried out with respect to concentration, time, pH, particle size and the thermodynamic evaluation of the process was carried at temperatures of 30, 40, 50 and 60(0C), respectively. The FTIR studies revealed that the potato peels was composed of –OH, -NH, –C=N, –C=C and –C-O-C functional groups. The optimum removal was obtained at pH 8 and contact time of 20 min. The adsorption process followed Freundlich adsorption and pseudo second-order kinetic models with correlation coefficients (R2) greater than 0.900. The equilibrium adsorption capacity showed that Pb(II) ion was more adsorbed on the surface of the potato peels biomass versus Cd (II) ion (200.91 mg/g &gt; 125.00 mg/g). The thermodynamic studies indicated endothermic, dissociative mechanism and spontaneous adsorption process. This study shows that sweet potato peels is useful as a low-cost adsorbent for the removal of Cd(II) and Pb(II) ions from aqueous medium.

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