Pb2+ adsorption by ethylenediamine-modified pectins and their adsorption mechanisms

Liang, Ruihong; Li, Ya; Huang, Li; Wang, Xuedong; Hu, Xiaoxue; Liu, Chengmei; Chen, Ming-shun; Chen, Jun

doi:10.1016/j.carbpol.2020.115911

Cited by 90 publications

(32 citation statements)

References 42 publications

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“…There is a broad band of 3395.5 cm −1 that appeared in the spectrum of pectin microspheres, which was assigned to stretching vibration of O-H groups. Two peaks at about 1627 cm −1 and 1441 cm −1 exhibited the vibrations of the carboxylate group (-COO) [ 24 ]. The typical bands of activated carbon were viewed at 1575.1 cm −1 assigned to the C=O peak of ketone or carbonyl, and the 1212.1 cm −1 was the C-O peak of aliphatic ether or phenol [ 25 ].…”

Section: Resultsmentioning

confidence: 99%

Pectin/Activated Carbon-Based Porous Microsphere for Pb2+ Adsorption: Characterization and Adsorption Behaviour

Wang

Shuai

et al. 2021

Polymers

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The development of effective heavy metal adsorbents has always been the goal of environmentalists. Pectin/activated carbon microspheres (P/ACs) were prepared through simple gelation without chemical crosslinking and utilized for adsorption of Pb2+. Scanning electron microscopy (SEM) revealed that the addition of activated carbon increased the porosity of the microsphere. Texture profile analysis showed good mechanical strength of P/ACs compared with original pectin microspheres. Kinetic studies found that the adsorption process followed a pseudo-second-order model, and the adsorption rate was controlled by film diffusion. Adsorption isotherms were described well by a Langmuir isotherm model, and the maximum adsorption capacity was estimated to be 279.33 mg/g. The P/ACs with the highest activated carbon (P/AC2:3) maintained a removal rate over 95.5% after 10 adsorption/desorption cycles. SEM-energy-dispersive X-ray spectrum and XPS analysis suggested a potential mechanism of adsorption are ion exchange between Pb2+ and Ca2+, electronic adsorption, formation of complexes, and physical adsorption of P/ACs. All the above results indicated the P/ACs may be a good candidate for the adsorption of Pb2+.

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Section: Resultsmentioning

confidence: 99%

Pectin/Activated Carbon-Based Porous Microsphere for Pb2+ Adsorption: Characterization and Adsorption Behaviour

Wang

Shuai

et al. 2021

Polymers

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“…As shown in Figure 6 A, the removal rate of Pb 2+ increased rapidly from pH 2.0 to 3.0, and then reached a plateau when the pH exceeded 3.0. This phenomenon was quite different from the other pectin-based Pb 2+ adsorbents, which usually showed an optimal adsorption pH of 5.0 [ 5 , 36 ]. The wider pH bearing range of the PPEAs may have been because the co-existence of PEI, which contains a high density of amino groups, changed the adsorption environment.…”

Section: Resultsmentioning

confidence: 70%

“…In China, the limit for lead in drinking water is 0.01 mg/L (GB 5749-2006). The excessive intake of Pb 2+ mainly harms the central nervous system, digestive system, reproductive system, liver, kidney, and bone marrow hematopoietic function of the human body [ 5 , 6 ].…”

Section: Introductionmentioning

confidence: 99%

Development of Pectin-Based Aerogels with Several Excellent Properties for the Adsorption of Pb2+

Wang

Shuai

et al. 2021

Foods

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Traditional aerogels lack specific functional groups for the adsorption of Pb2+, which results in a low adsorption capacity and limits the application scope. Novel porous pectin-based aerogels (PPEAs) were prepared by incorporating polyethylenimine (PEI) using ethylene glycol diglycidyl ether (EGDE) as a cross-linker for the removal of Pb2+ from water. The cross-linking mechanism, morphology, mechanical strength, thermal stability, adsorption properties, and mechanism of the aerogels were investigated. The aerogels possessed several desirable features, such as a large maximum Pb2+ adsorption capacity (373.7 mg/g, tested at pH 5.0), ultralight (as low as 63.4 mg/cm3), high mechanical strength (stress above 0.24 MPa at 50% strain), and easy recyclability. Meanwhile, the equilibrium adsorption data was well described by the Langmuir–Freundlich (Sips) model and the kinetic adsorption process was well fitted using the pseudo-second-order model. The donor groups, such as -NH2, and oxygen-containing functional groups were responsible for the Pb2+ adsorption, which was confirmed by the FTIR and XPS analysis. The excellent characteristics mean that PPEAs are highly effective adsorbents in the remediation of lead-containing wastewater.

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“…Both the degree of esterification and the degree of amidation of pectin can be determined by titration experiments, while for the accuracy of experimental data, the degree of esterification of pectin samples can be confirmed by NMR method, and the degree of amidation of amidated pectin can be calculated by elemental analysis (Liang et al, 2020; Nakamura et al, 2002). The results of the titration method are employed as a reference in subsequent experiments.…”

Section: Methodsmentioning

confidence: 99%

Study on the influencing factors of natural pectin's flocculation: Their sources, modification, and optimization

Shao

Zhang

et al. 2021

Water Environment Research

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Natural pectin, derived from fruit residue, presented a certain flocculation performance in previous studies. However, the process of extraction and treatment affected the flocculation performance considering the uncontrollable chemical composition and the molecule structure. In this study, degree of esterification (DE), degree of amidation (DA) were used as the internal factors affecting flocculation performance. The DE/DA values of pectin were obtained through FTIR, elemental analyses, H‐NMR, and titration measurements. The kaolin suspension was employed for the coagulation jar tests, and the removal of NTU (Nephelometric Turbidity Unit) was used as the index of the flocculation performance. Results showed that the flocculation performance of pectin arising from different fruits was different, which was associated with the various preparation processes. By introducing polar groups into pectin, the flocculation was found to be related to bridging, adsorption, and charge neutralization. Based on the trends of three‐dimensional response surfaces, the flocculation effect was improved with the decreased DE and the increased DA. The optimized amidated pectin was obtained by the amidation experiment, the turbidity reduction in wastewater was 99.63%. Practitioner points The internal influencing factors of pectin as a flocculant were investigated. Different sources of pectin show different flocculation ability. Amidation modification can improve the flocculation performance of pectin. Response surface method to study the interaction of different influencing factors. Pectin may replace synthetic flocculants in water treatment.

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Pb2+ adsorption by ethylenediamine-modified pectins and their adsorption mechanisms

Cited by 90 publications

References 42 publications

Pectin/Activated Carbon-Based Porous Microsphere for Pb2+ Adsorption: Characterization and Adsorption Behaviour

Pectin/Activated Carbon-Based Porous Microsphere for Pb2+ Adsorption: Characterization and Adsorption Behaviour

Development of Pectin-Based Aerogels with Several Excellent Properties for the Adsorption of Pb2+

Study on the influencing factors of natural pectin's flocculation: Their sources, modification, and optimization

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