Desalination and Water Treatment
·
2024
·
IF 1
Zhenyu Wang,Zhu Tu,Lulu Lu,Zefeng Wang,Minghua Yang
The addition of the surfactant can greatly reduce the moisture content of the sludge. But little research has been done on the synthesis of surfactants and the mechanism of dehydration. Thus, a novel cationic surfactant ZWY-28 with higher surface activity and more surface charge was investigating for sludge dewatering in this research. Results showed that when the content of ZWY-28 was 1% (0.14 g/L), the specific resistance to the filtration of sludge had a minimum value of 2.04 × 10 12 m/kg, the moisture content of the dehydrated sludge cake reached a minimum of 78.9%, the bound water reduced to 6.32 g/g, decreased by 39.2%. What’s more, the ZWY-28 is extremely helpful in releasing Extracellular polymers substances from sludge, lead to the removal of bound water, which is the key point of affecting sludge dewatering. The study clearly illustrated that the surfactant ZWY-28 accelerated the dewatering process and could be used as a potential agent for sludge. Meanwhile, it provides ideas for the selection and structure design of surfactants in sludge dewatering.
研究领域:
环境工程
·
胶体与界面化学
·
废水处理
·
污泥处理
✓ 已验证
DOI
高影响因子
WATER RESEARCH
·
2019
·
IF 7.913
Yang Lv,Keke Xiao,Jiakuan Yang,Yuwei Zhu,Kangyue Pei,Wenbo Yu,Shuangyi Tao,Hui Wang,Sha Liang,Huijie Hou,Bingchuan Liu,Jingping Hu
Pre-oxidation is effective in enhancing sludge dewaterability. Different types and doses of oxidants are used to improve sludge dewaterability in pre-oxidation. Rapid evaluation of the sludge dewaterability is vital for optimizing the type and dose of oxidants in pre-oxidation. It normally takes more time to evaluate sludge dewaterability by measuring typical indicators such as specific resistance to filtration (SRF), content of bound water, and composition of EPS. This study presented a rapid parameter, oxidation-reduction potential (ORP), to correlate it with the dewaterability of pre-oxidized sludge samples. An index of ΔORP (ΔORP = ORP t=0.5 min –ORP t=0 min ) showed positive correlations with SRF ( r = 0.89, p < 0.05), content of total organic carbon in soluble and loosely-bound EPS ( r = 0.86 and 0.84, p < 0.05), zeta potential ( r = 0.86, p < 0.05), and content of Fe(III) in the sludge cake ( r = 0.92, p < 0.01). However, the ΔORP index showed negative correlations with tryptophan-like proteins, tyrosine-like proteins, microbial byproduct-like materials in tightly-bound EPS ( r = −0.85, −0.90 and −0.90, p < 0.05), and sludge particle sizes ( p < 0.01). A multiple linear regression model was developed to further reflect the linear correlation between the ΔORP values and the key factors reflecting sludge dewaterability. An optimal dose of oxone (0.4 mmol/g VS) for sludge pre-oxidation with the ΔORP value of 387 mV combined with Fe(III) coagulation conditioning system were verified by the results of dewatering experiments using a laboratory-scale diaphragm filter press. This study demonstrated the feasibility of using ΔORP as a potential rapid evaluation tool for sludge dewaterability.
研究领域:
环境工程
·
水处理
·
污水处理
✓ 已验证
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Juanjuan Wan,Lijuan Zhang,Bo Yang,Boyu Jia,Jiakuan Yang,Xintai Su
Enzymes have important advantages in sludge dewatering , but their catalytic performance is limited by their poor activity and stability. To address this issue, we develop a series of immobilized enzymes (immobilized acid protease, IE 1; immobilized pectinase, IE 2; immobilized laccase, IE 3) prepared by the electrostatic interaction between the Fe 3 O 4 @SiO 2 -NH 2 as immobilized carrier and the free enzyme, and used for sludge dewatering. As-obtained immobilized enzymes endowed high efficiency and stable sludge dewatering performance in a wide pH range, and had the best dewatering performance when the pH was 5. Specifically, the specific resistance filtration (SRF) performance of the immobilized enzyme at pH 5 was better than that of the control group, and the order was FE 3, 3.84 × 10 13 m kg −1 > FE 1, 2.52 × 10 13 m kg −1 > CL 1, 2.16 × 10 13 m kg −1 > CL 2, 1.34 × 10 13 m kg −1 > FE 2, 2.06 × 10 13 m kg −1 > IE 2, 0.89 × 10 13 m kg −1 > IE 1, 0.82 × 10 13 m kg −1 > IE 3, 0.73 × 10 13 m kg −1 . Such improvement is attributed to two respects: Firstly, the immobilized enzyme has good activity, stability, and abundant functional groups on the surface, which is conducive to the attachment and continuous decomposition of organic matter. Secondly, the solid immobilized carrier can construct the skeleton structure in situ and effectively promote the release of water in sludge. This study provides a feasible way for the practical application of biological enzyme in sludge dewatering.
研究领域:
环境工程
·
生物技术
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CARBON
·
2025
·
IF 11.6
Yuqin Zeng,Haibo Feng,Ling Ling,Li Li
Hierarchical architectures offer a new framework for enhancing specific damping in composites. However, effectively integrating multiscale damping sources with dynamic excitation remains challenging. Cross-scale damping mechanisms are difficult to control. To address this, this study proposes a multiscale damping design principle centered on the balanced-relative strain factor and normalized strain index. A multiscale design strategy for carbon-fiber-reinforced polymers is developed, successfully achieving ultra-high specific damping performance. The resulting composite exhibits an outstanding loss modulus of 13.2 GPa, exceeding conventional engineering materials. Its tensile yield strength reaches 441.8 MPa, demonstrating suitability for high-strength applications. Simulations are also employed to analyze the damping enhancement mechanism. This work provides a novel strategy for the design and manufacturing of lightweight, high-performance, and multifunctional structural damping composites.
研究领域:
材料科学
·
复合材料工程
·
结构功能一体化材料
·
力学与材料学
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
·
2019
·
IF 5.108
Hua Wei,Yunong Tang,Tamer Shoeib,Aimin Li,Hu Yang
The preoxidation effects of H 2 O 2 , NaClO, and KMnO 4 on the dewaterability of sewage sludge were compared by analyzing the changes in specific resistance to filtration (SRF), filter cake moisture content (FCMC), extracellular polymeric substance (EPS) fractions and components, and floc properties. The three oxidants varied in oxidation efficiency and exhibited distinctive mechanisms. NaClO not only destroyed sludge flocs and EPSs but also effectively caused cell lysis, resulting in release of a considerable amount of organic matters and subsequently significant deterioration of dewatering performance. The oxidation of H 2 O 2 and KMnO 4 was relatively mild and occurred mainly on the outer layers of the sludge flocs and cell-bound EPSs. By contrast, the SRF and FCMC of the sludge conditioned with a low dose of KMnO 4 were slightly improved, and a fraction of soluble EPS was compressed because of the coagulation effect of the oxidation product MnO 2 . The pH of the sludge conditioned with H 2 O 2 and KMnO 4 showed no considerable change. Meanwhile, NaClO evidently increased the alkalinity of the sludge because of the hydrolysis effect. After the pH of the NaClO-treated sludge was readjusted to 7.0, the partial protonation efficiency slightly alleviated the deterioration of sludge dewatering performance. The preoxidized sludge was then subjected to reflocculation treatment using FeCl 3 , polyacrylamide, and a cationic starch-based flocculant , respectively. The combined treatment of preoxidation and reflocculation showed a high dewatering efficiency owing to their synergistic effect.
研究领域:
环境工程
·
水处理
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2022
·
IF 10.753
Nannan Geng,Yili Wang,Daxin Zhang,Xiaoyang Fan,Enrui Li,Zhibo Han,Xiaoqi Zhao
As a by-product of wastewater treatment , waste activated sludge (WAS) has complex composition, strong hydrophilic extracellular polymeric substance (EPS), which make it difficult to dewater. In this study, an electro-peroxone oxidation-Fe(III) coagulation (E-peroxone-Fe(III)) sequential conditioning approach was developed to improve WAS dewaterability. At E-peroxone oxidation stage, hydrogen peroxide was generated through 2-electron path on a carbon polytetrafluoroethylene cathode, and reacted with the sparged O 3 to produce hydroxyl radicals . At the subsequent coagulation stage, Fe(III) was dosed to coagulate the small WAS fragments and release water from WAS. Along E-peroxone-Fe(III) subsequent conditioning process, the physicochemical properties of WAS, main components, functional groups and evolution of protein secondary structure, and typical amino acids in EPS, as well as the type and semi-quantitative of elements in WAS, were investigated. The results indicated that under the optimal conditions, the reductions of specific resistance to filterability (SRF) and capillary suction time (CST) for WAS equalled 78.18% and 71.06%, respectively, and its bound water content decreased from 8.87 g/g TSS to 7.67 g/g TSS. After E-peroxone oxidation, part of protein and polysaccharide migrated outside from TB-EPS to slime, the ratio of α-helix/( β -sheet + random coil) declined, even some of organic-N disintegrated to inorganic-N. At Fe(III) coagulation stage, re-coagulation of the dispersed WAS fragments and easy extraction from inner EPS for protein and polysaccharide occurred. Furthermore, the protein secondary structure of β -sheet increased by 13.48%, the contents of hydrophobic and hydrophilic amino acids also increased. In addition, a strong negative correlation between the hydrophobic amino acid content of Met in slime and CST or SRF ( R 2 CST = −0.999, p < 0.05 or R 2 SRF = −0.948, p < 0.05) occurred, while a strong positive correlation between the hydrophilic amino acid content of Cys in TB-EPS and CST or SRF ( R 2 CST = 0.992, p < 0.05 or R 2 SRF = 0.921, p < 0.05) occurred, which could be related to the WAS dewaterability.
研究领域:
环境工程
·
污水处理
·
污泥管理
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ENVIRONMENTAL MANAGEMENT
·
2018
·
IF 4.005
Hua Wei,Pan Hu,Aimin Li,Hu Yang
Conditioning is essential for achieving effective sludge dewatering and easier disposal. In this study, a combined pretreatment of acidification and oxidation using potassium permanganate (KMnO 4 ) as oxidant was conducted to improve the effect of a cationic starch-based flocculant (St-WH) on the dewaterability of sewage sludge . Synergetic dewatering mechanisms by acidification, oxidation, and flocculation are discussed in detail according to the analysis of the changes in bound water content, extracellular polymeric substances (EPS) fractions and components, zeta potentials , floc size, and surface microstructures of sludge cakes in the dewatering process. Acidification and oxidation could destroy the sludge flocs, thereby causing the degradation of EPS and formation of fine particles. Original loosely and tightly bound EPS partially converted to soluble EPS, resulting in release of trapped water, which can be reflected by the significant correlation between loosely bound EPS and filter cake moisture content (FCMC) ( R s = 0.83, P < 0.05). Those fine particles, simultaneously produced, were adverse to filtration efficiency . In addition to enhancing the oxidation effect of KMnO 4 , acidification treatment could still compress the protein-like materials in soluble EPS due to protonation effect, which was positively related to specific resistance to filtration (SRF) ( R s = 0.74, P < 0.05). The following flocculation using St-WH efficiently aggregated those fine particles and restrained the released EPS to bind with free water through charge neutralization and bridging effects, thereby resulting in improved filtration performance and enhanced removal of bound water ( R s = 0.88, P < 0.01). Response surface methodology was also applied to achieve an optimal condition and evaluate the effects of various environmental factors.
研究领域:
环境工程
·
水处理
·
废水管理
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2024
·Vol. 14
·期 25
·17547-17556
·
IF 3.9
Shilei Tang,Shaobin Huang,Pengfei Chen,Zhipeng Wu,Tianyu Zhao
Dredged sediment poses significant challenges for transportation and subsequent treatment due to its high water content and large volume. Coagulation, a common method of dewatering, can significantly enhance the dewatering performance of dredged sediment. This study synthesized a cationic starch-based flocculant [starch-3-chloro-2-hydroxypropyl trimethylammonium chloride (St-CTA)] through etherification for the flocculation dewatering of dredged sediment. The effectiveness and mechanism of St-CTA as a dewatering flocculant for dredged sediment were investigated. The results demonstrated that when the dosage of St-CTA was 12 mg g−1 TSS (total suspended solids), the dehydration property of dredged sediment substantially improved, with the specific resistance to filtration (SRF) decreasing by 93.3%, the capillary suction time (CST) by 93.5%, and the water content of the filter cake (WC) by 9.7%. The removal rate of turbidity of the supernatant from the conditioned dredged sediment reached 99.6%, accelerating the settling speed and effectively capturing and separating fine particles from the sediment. St-CTA significantly increased the median particle size (D50), altered the microstructure and extracellular polymeric substances (EPS) of the flocs, and increased the fractal dimension of the flocs, making them more compact and conducive to the formation of drainage channels. These findings confirm the feasibility of using potentially environmentally friendly St-CTA as a rapid dewatering conditioning agent for sediment.
研究领域:
环境工程
·
水处理
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）