Biopolymer Hydrogel-Based Salt-Resistant Evaporator for Solar-Energy-Driven Desalination and Water Purification.

Interfacial solar steam generation (ISSG) has recently received much attention as a low-carbon-footprint and high-energy-efficient strategy for seawater desalination and wastewater treatment. However, achieving the goals of a high evaporation rate, ecofriendliness, and high tolerance to salt ions in brine remains a bottleneck. Herein, a novel hydrogel-based evaporator for effective solar desalination was synthesized on the basis of sodium alginate (SA) and carboxymethyl chitosan (CMCS) incorporating a carbon nanotube (CNT)-wrapped melamine sponge (MS) through a simple dipping-drying-cross-linking process. The hydrogel-based evaporator reaches a high evaporation rate of 2.18 kg m-2 h-1 in 3.5 wt % brine under 1 sun irradiation. Furthermore, it demonstrated excellent salt ion rejection in high-concentration salt water. Simultaneously, it exhibits excellent purification functionality toward heavy metals and organic dyes. This study provides a simple and efficient strategy for seawater desalination and wastewater treatment.

Prevalence of transmissible gastroenteritis among swine populations in China during 1983-2022: A systematic review and meta-analysis.

BACKGROUND: Transmissible gastroenteritis virus (TGEV), which belongs to the coronaviruses (CoVs), causes diarrhea and high mortality rates in piglets and poses a huge threat and loss to the pig industry in China. METHOD: We estimated the prevalence of TGEV in Chinese pig animals from 1983 to 2022 by screening 36 papers on TGEV investigations in China from databases such as China Knowledge Network (CNKI), Wanfang Database, Science and Technology Journal Repository (VIP), PubMed, and ScienceDirect, excluding duplicate literature and other host studies according to the exclusion criteria we developed, and excluding literature with incomplete data to extract information from studies that could estimate the prevalence of TGEV infection in pigs in mainland China. RESULTS: A total of 36 studies (including data from 50,403 pigs) met our evaluation criteria. The overall estimated prevalence of TGEV infection in pigs in China is 10% (3887/50403), and the prevalence of TGEV in northeast China is 38% (2582/3078700) is significantly higher than the rest of China. The prevalence of TGEV infection was related to the sampling season and region. CONCLUSION: The results of the study show that the prevalence of TGEV is clearly seasonal and regional. Therefore, further research and monitoring of the prevalence of TGEV infection and the development of control programs based on different conditions are essential. In addition, effective and robust regulatory measures should be taken in colder regions to prevent the spread and transmission of TGEV in pigs.

Prevalence of bovine rotavirus among cattle in mainland China: A meta-analysis.

BACKGROUND: Bovine rotavirus is the primary pathogen causing diarrhea in cattle and can be transmitted vertically through the placenta. It mainly presents with clinical signs such as depression, loss of appetite, diarrhea, vomiting, and dehydration. METHODS: A systematic review and meta-analysis were conducted to assess the prevalence of BRV infection in mainland China. We conducted a literature search on the prevalence of BRV infection in pigs between Jan 1, 1979 and Dec 31, 2021 in English and Chinese databases, including PubMed, Google Scholar, Cochrane library, Clinical Trials, VIP, CNKI, and WanFang database. Selections were made based on the title and the abstract of the paper, Search strings included if they reported the cattle samples of more than 15 cattle and provided information that allowed us to establish the prevalence of BRV. Moreover, we excluded repeated studies, reviews, other hosts. Finally, we extracted the number of cattle with BRV infection from the obtained studies and provided information that permitted us to estimate the prevalence of BRV infection in cattle in mainland China. RESULTS: The data of 29 articles (including data on 10677 cattle) are compliant with the standards. The pooled prevalence of BRV in cattle in China was 46%（6635/10677）, the pooled prevalence of BRV in cattle from Northeast China (40%) was significantly lower than those from other regions. In addition, the prevalence of BRV was associated with publication time of paper, detection methods, age of cattle, and clinical symptoms（diarrhea, etc.). CONCLUSION: Our findings suggest that BRV infection is common among cattle in China. It is, therefore, necessary to carry out further research and monitor the prevalence of BRV infection. Furthermore, powerful and effective regulatory measures should be taken to prevent the transmission and spread of BRV among cattle populations.

Surveillance of multiple subtype specific antibodies against avian influenza viruses among egg yolk in wild ducks from northeast China, 2017-2019.

Over the past decade, various avian influenza viruses have been isolated from wild ducks found in the northeast of China. To monitor the prevalence of multiple subtype specific AIVs antibodies, 1705 wild ducks' eggs from six wetlands of northeast China were analyzed for surveillance of H1, H3, H5, and H7 AIVs antibodies by c-ELISA and HI test from Jan 2017 to Dec 2019. The results show that the combined frequency of multiple subtype specific AIVs antibodies were H1 (12.32%), H3 (8.15%), H5 (2.05%), and H7 (3.46%) respectively. Therefore, a detailed analysis of the geographical distribution of AIVs in China, and the risk factors for human infection is of vital importance. This study provides basic data for other researchers to deeply study AIVs distribution characteristics, and for governments to develop detailed measures to control the spread of AIVs.

Seroprevalence of influenza A (H9N2) virus infection among humans in China: A meta-analysis.

Herein, we conducted a meta-analysis aimed at comprehensively assessing avian influenza A (H9N2) virus infection seroprevalence and infection-related risk factors among humans in China. We reviewed published studies pertaining to H9N2 seroprevalence of in China from inception to March 20, 2020, with PubMed, Clinical Trial, VIP, CNKI and databases being used to identify English and Chinese articles. After excluding the incomplete literature and data, 45 studies about risk factor of human H9N2 viral infections in China were analyzed by systematic review and meta-analysis. Our results showed that 45 studies (59,590 total patients) met the inclusion criteria. Overall H9N2 infection seroprevalence in China was estimated to be 5.56% (95%CI = 3.88-7.28), while that from central China the seroprevalence was 22.72% (95%CI = 12.18-33.84), with this prevalence being greater than that observed in other regions. H9N2 infection seroprevalence was related to sampling time, testing methodology, gender, and other demographic factors. This review will provide a basis for further understanding the risk factors of H9N2 infections in China, and it is necessary to study how to formulate strict and targeted measures to prevent the spread of the virus.

Technical note: Development of a closed-tube isothermal multiple self-matching-initiated amplification assay for visual detection of Staphylococcus aureus in milk samples.

Staphylococcus aureus is one of the most common mastitis-causing bacteria in dairy cows. It is associated with reduced production performance in animals and with huge financial losses for the dairy industry worldwide. An accurate and sensitive method for the early diagnosis and identification of Staph. aureus in milk samples is essential. The present study aimed to establish a closed-tube isothermal multiple self-matching-initiated amplification (IMSA) technique for visual confirmation of the presence of Staph. aureus targeting the nuc conserved sequence gene. The specific primers successfully amplified the target sequence within 45 min at 63°C reaction temperature and using the optimal components of the reaction system. The positive amplicon showed bright green fluorescence under UV light when mixed with the chromogenic substrate SYBR Green I, and the negative samples remained orange in color. We observed fluorescence and a ladder-like pattern in the IMSA amplicon for all Staph. aureus strains, and we observed no significant change for the non-Staph. aureus strains. The IMSA assay had high specificity compared with loop-mediated isothermal amplification (LAMP): it confirmed the presence of all 7 Staph. aureus strains, and we found no false-positive results for the 12 non-Staph. aureus strains. The lower limit of detection for the IMSA assay was 1 × 102 cfu/mL, 10-fold more sensitive than the results obtained using LAMP. We also successfully applied the IMSA assay to confirm the presence of Staph. aureus in milk samples of cows with mastitis, and the results were consistent with those of LAMP and real-time PCR. The present study reports the use of IMSA to confirm the presence of Staph. aureus and provides a potentially useful method for rapid preliminary screening for Staph. aureus.

Prevalence of avian influenza viruses and their associated antibodies in wild birds in China: A systematic review and meta-analysis.

Avian influenza viruses (AIVs) in wild birds pose a pandemic threat to humans and to the poultry industry. To assess AIV and AIV antibody prevalence in wild birds in China, a systematic review and meta-analysis were conducted. We searched PubMed, Google Scholar, Cochrane Library, Clinical Trial, VIP, CNKI, and WANFANG for published papers related to the prevalence of AIVs and their associated antibodies in wild birds in China from Mar. 10, 2005 to Sept. 20, 2018. Repeat studies, reviews, and other host studies were excluded, as well as those with inconsistent data, incomplete information, or only prevalence data or data from outside of mainland China. In total, data from 28 publications were compiled and analyzed. Based on out meta-analysis, the pooled prevalence of AIVs in wild birds in China was found to be 2.5% (571/23,024), and the pooled prevalence of AIV antibodies was 26.5% (1,210/4,566). The pooled prevalence of AIVs was significantly higher in wild birds from Central China (5.5%, 271/4, 955) compared to all other regions and the pooled prevalence of AIV antibodies was significantly in wild birds from South China (56.8%, 92/162) in comparison to all other regions. The prevalence of both AIVs and AIV antibodies in Anseriformes were higher compared to non-Anseriformes. In addition, the largest number of studies found in this review were on the HA subtypes of AIVs (H5, H7, and H9) and their associated antibodies. In summary, our findings suggest that the prevalence of AIVs and their antibodies in wild birds vary among regions and species of wild bird. Thus, further monitoring of the prevalence of AIVs and their antibodies in wild birds in China is necessary and should be used for guiding powerful and effective regulatory measures that will prevent the spread of AIVs across species.

Epidemiology of porcine epidemic diarrhea virus among Chinese pig populations: A meta-analysis.

BACKGROUND: Porcine epidemic diarrhea results from infection with porcine epidemic diarrhea virus (PEDV). It is an acute and highly contagious enteric disease in swine characterized by watery diarrhea and vomiting. Here, we performed a systematic review and meta-analysis in order to assess the prevalence of PEDV infection in pig populations from mainland China. METHODS: We conducted a literature search on the prevalence of PEDV infection in pigs between Jan 1, 1988 and Aug 20, 2018 in English and Chinese databases, including PubMed, Google scholar, Cochrane library, Clinical Trials, VIP, CNKI and WanFang database. Selections were made based on the title and the abstract of paper, and duplicated literature was excluded along with other host studies, and data incomplete literature according to the exclusion criteria we formulated. Finally, we extracted the number of swine with PEDV infection from the obtained studies and provided information that permitted us to estimate the prevalence of PEDV infection in pigs in mainland China. RESULTS: A total of 45 studies (including data from 15,990 pigs) met our evaluation criteria. In China, the overall estimated prevalence of PEDV infection in pigs was 44% (7113/15,990), while the estimated prevalence of PEDV infection in pigs from northern China was 37% (793/2136), lower than those in other regions of China. The prevalence of PEDV infection was associated with sampling season, category of pigs and clinical signs (diarrhea) in pigs. However, the prevalence of PEDV among pigs in China was not significantly associated with the effect of detected target genes, nor was it associated with date of study publication. CONCLUSION: Our findings suggest that PEDV infection is common among pigs in China. It is therefore necessary to carry out further research and monitor the prevalence of PEDV infection. Furthermore, powerful and effective regulatory measures should be taken in order to prevent the transmission and spread of PEDV among pig populations.

A doubled increasing trend of evapotranspiration on the Tibetan Plateau.

Estimation of evapotranspiration (ETa) change on the Tibetan Plateau (TP) is essential to address the water requirement of billions of people surrounding the TP. Existing studies have shown that ETa estimations on the TP have a very large uncertainty. In this article, we discuss how to more accurately quantify ETa amount and explain its change on the TP. ETa change on the TP can be quantified and explained based on an ensemble mean product from climate model simulations, reanalysis, as well as ground-based and satellite observations. ETa on the TP experienced a significant increasing trend of around 8.4 ± 2.2 mm (10 a)-1 (mean ± one standard deviation) during 1982-2018, approximately twice the rate of the global land ETa (4.3 ± 2.1 mm (10 a)-1). Numerical attribution analysis revealed that a 53.8% TP area with the increased ETa was caused by increased temperature and 23.1% part was due to soil moisture rising, because of the warming, melting cryosphere, and increased precipitation. The projected future increase in ETa is expected to cause a continued acceleration of the water cycle until 2100.

Prevalence of clinical mastitis and its associated risk factors among dairy cattle in mainland China during 1982-2022: a systematic review and meta-analysis.

Background: Bovine mastitis is one of the most common and prevalent diseases affecting dairy cattle worldwide. It adversely affects the quality and quantity of milk production and leads to a significant economic loss for the farmers. Methods: This article aimed to estimate the prevalence of clinical mastitis (CM) infection in mainland China using a systematic review and meta-analysis. The research reports published during 1983-2022 in English or Chinese from databases (PubMed, Google Scholar, Cochrane Library, Science Direct, Web of Science, VIP Database for Chinese Technical Periodicals (VIP), Chinese National Knowledge Infrastructure (CNKI), and Wan Fang database) were identified after reviewing the relevant scientific literature. Based on our inclusion criteria, this study analyzed the prevalence of CM in 47 published studies prevalence extracted the total number of cattle infected with CM from the available studies, allowing us to estimate the prevalence of CM infection among these in mainland China. Results: The pooled prevalence with the 95% CI for the clinical mastitis was 10% (95% CI: 9.00, 12.00). The majority of CM was associated with lactation, parity, and age, with higher prevalence observed in late lactation 15% (95% CI: 11.00, 18.00) and mid-lactation 10% (95% CI: 6.00, 13.00) in comparison to early lactation 8% (95% CI: 5.00, 10.00). The incidence of CM increased significantly with the increase of parity and age, and the highest incidence rates were 19% (95% CI: 15.00, 23.00) and 16% (95% CI: 12.00, 19.00) at parity and age ≥7, respectively. Among the seasons, the highest prevalence of CM infection was found in autumn 9% (95% CI: 2.00, 17.00). Interestingly, no significant effects were evident regarding the influence of quarter on the prevalence of CM. Conclusion: Thus, estimating the prevalence of CM among cattle in mainland China. through meta-analysis can provide adequate measures to control CM, reduce economic losses, and prevent the spread and transmission of CM in Chinese herds.

Persistent and enhanced carbon sequestration capacity of alpine grasslands on Earth's Third Pole.

The carbon sequestration capacity of alpine grasslands, composed of alpine meadows and steppes, in the Tibetan Plateau has an essential role in regulating the regional carbon cycle. However, inadequate understanding of its spatiotemporal dynamics and regulatory mechanisms restricts our ability to determine potential climate change impacts. We assessed the spatial and temporal patterns and mechanisms of the net ecosystem exchange (NEE) of carbon dioxide in the Tibetan Plateau. The carbon sequestration of the alpine grasslands ranged from 26.39 to 79.19 Tg C year-1 and had an increasing rate of 1.14 Tg C year-1 between 1982 and 2018. While alpine meadows were relatively strong carbon sinks, the semiarid and arid alpine steppes were nearly carbon neutral. Alpine meadow areas experienced strong increases in carbon sequestration mainly because of increasing temperatures, while alpine steppe areas had weak increases mainly due to increasing precipitation. Carbon sequestration capacity of alpine grasslands on the plateau has undergone persistent enhancement under a warmer and wetter climate.

Thermal Stability Improvement of Core Material via High Internal Phase Emulsion Gels.

Biocompatible particle-stabilized emulsions have gained significant attention in the biomedical industry. In this study, we employed dynamic high-pressure microfluidization (HPM) to prepare a biocompatible particle emulsion, which effectively enhances the thermal stability of core materials without the addition of any chemical additives. The results demonstrate that the HPM-treated particle-stabilized emulsion forms an interface membrane with high expansion and viscoelastic properties, thus preventing core material agglomeration at elevated temperatures. Furthermore, the particle concentration used for constructing the emulsion gel network significantly impacts the overall strength and stability of the material while possessing the ability to inhibit oxidation of the thermosensitive core material. This investigation explores the influence of particle concentration on the stability of particle-stabilized emulsion gels, thereby providing valuable insights for the design, improvement, and practical applications of innovative clean label emulsions, particularly in the embedding and delivery of thermosensitive core materials.

The function of Foxp1 represses ß-adrenergic receptor transcription in the occurrence and development of bladder cancer through STAT3 activity.

Bladder cancer is a common malignant tumor. FOXP1 has been found to be abnormally expressed in tumors such as renal cell carcinoma and endometrial cancer. Here, this investigated the biological roles of Foxp1 in the occurrence and development of bladder cancer. Patients with bladder cancer were obtained from China-Japan Friendship Hospital. Bladder cancer cell lines (5637, UMUC3, J82, and T24 cell) were used in this experiment. Foxp1 mRNA and protein expression levels in patients with bladder cancer were increased, compared with paracancerous tissue (normal). OS and DFS of Foxp1 low expression in patients with bladder cancer were higher than those of Foxp1 high expression. Foxp1 promoted bladder cancer cell growth in vitro model. Foxp1 increased the Warburg effect of bladder cancer. Foxp1 suppressed ß-adrenoceptor (ß-AR) expression in vitro model. ChIP-seq showed that Foxp1 binding site (E1, TTATTTAT) was detected at -2,251 bp upstream of the ß-AR promoter. ß-AR Reduced the effects of Foxp1 on cell growth in vitro model. ß-AR reduced the effects of Foxp1 on the Warburg effect in vitro model by STAT3 activity. Taken together, our findings reveal that Foxp1 promoted the occurrence and development of bladder cancer through the Warburg effect by the activation of STAT3 activity and repressing ß-AR transcription, and which might serve as an important clue for its targeting and treatment of bladder cancer.

Diagnostic accuracy of dual-energy CT for bone marrow edema in patients with acute knee injury: a systematic review and meta-analysis.

BACKGROUND: Knee injuries are prevalent, and early diagnosis is crucial for guiding clinical therapy. MRI is the diagnostic gold standard for bone marrow edema (BME) in patients with acute knee injuries, yet there are still limitations. Dual-energy CT, a possible viable replacement, is being explored (DECT). METHODS: We systematically retrieved studies from EMBASE, Scopus, PUBMED, and the Cochrane Library and collected gray literatures. In accordance with the PRISMA-DTA standards, a systematic review was conducted between the study's initiation and July 31, 2021, utilizing an MRI reference standard and at least 10 adult patients with acute knee injuries to evaluate the diagnostic effectiveness of DECT for diagnosing BME. Two reviewers collected the study's details independently. For the meta-analysis, a bivariate mixed-effects regression model was utilized, and subgroup analysis was employed to determine the sources of variability. RESULTS: The research included nine studies that examined 290 individuals between the ages of 23 and 53 with acute knee injuries who had DECT and MRI. Overall, the sensitivity, specificity, and AUC of the BME were 85% (95% confidence interval [CI]: 77-90%), 96% (95% CI: 93-97%), and 0.97 (95% CI: 0.95-0.98), respectively. To account for the assumed diversity of research, there were no statistically significant differences between the comparison groups in terms of specificity and sensitivity. CONCLUSION: DECT is a viable alternative to MRI for individuals with acute knee injuries when MRI is inappropriate or unavailable.

Prevalence of subclinical mastitis among dairy cattle and associated risks factors in China during 2012-2021: A systematic review and meta-analysis.

Bovine mastitis, especially subclinical mastitis (SCM), is one of the most prevalent and economically costly diseases in the dairy industry worldwide. Understanding the prevalence and spatial distribution of bovine SCM and its associated risk factors will facilitate the prevention and control of the disease. We reviewed published studies pertaining to epidemiological surveys of SCM among dairy cows during the past decade (2012-2021) in China from inception to March 20, 2020, with PubMed, Clinical Trial, VIP, CNKI and databases being used to identify English and Chinese articles. Therefore, we retrieved 41 studies related to epidemiological surveys of SCM among dairy cows, using our eligibility criteria. We demonstrated that the prevalence of SCM in dairy cows was 37.7% during the selected periods, indicating a slight increase in the incidence of SCM in a comparison between 2012 and 2016 and 2017-2021. The estimated prevalence of SCM was 36.4%-50.2% in the seven regions, which was no statistically significant difference. The highest prevalence of SCM was 72% in Inner Mongolia Autonomous Region, and the lowest prevalence was 19% in Hubei Province. The variation in diagnostic methods was not significant in the studies. Dairy cows' parity was a risk factor associated with the prevalence rate of SCM. Cow's age might affect the prevalence of SCM during the selected periods. This study may facilitate the control with specific strategies to reduce costs and antibiotics overuse, enhance food safety and public health.

Dual-Layer Multichannel Hydrogel Evaporator with High Salt Resistance and a Hemispherical Structure toward Water Desalination and Purification.

Interfacial solar steam generation technology has been considered as one of the most promising methods for seawater desalination. However, in practical applications, salt precipitation on the evaporation surface reduces the evaporation rate and impairs long-term stability. Herein, a dual-layer hydrogel-based evaporator that contains a microchannel-structured water-supplying layer and a nanoporous light-absorbing layer was synthesized via sol-gel transition and "hot-ice" template methods. Contributed by the designed structure-induced accelerated salt ion exchange, the hemispherical dual-layer hydrogel evaporator showed excellent salt formation resistance property, as well as a high evaporation rate reaching 2.03 kg m-2 h-1 even under high brine concentration conditions. Furthermore, the hydrogel-based evaporator also demonstrated excellent ion rejection, high/low pH tolerance, and excellent purification properties toward heavy metals and organic dyes. It is believed that this type of dual-layer multichannel evaporator is promising to be used in seawater desalination, water pollution treatment, and other environmental remediation-related applications.

Negative impacts of human disturbances on the seed bank of subalpine forests are offset by climatic factors.

Precipitation and temperature in the subalpine region have increased dramatically in recent decades due to global warming, and human disturbances have continued to impact the vegetation in the region. Seed bank plays an important role in population recovery, but there are few studies on the synergistic effects of human disturbances and climate change on seed bank. We analyzed the synergistic effects of human disturbances and climate change on seed bank samples from 20 sites in the subalpine coniferous forest region using grazing and logging as the disturbance intensity gradient and precipitation and temperature as climate variables. The species diversity of aboveground vegetation all changed significantly (p < 0.05) with precipitation, temperature and disturbance level, while the seed bank richness and density did not. Furthermore, the species composition of the seed bank varied significantly less than that of the aboveground vegetation at different levels of disturbance (p < 0.001). Thus, seed bank showed a strong buffering capacity against the risk of local extinction caused by environmental changes that shift the species composition and diversity of aboveground vegetation. In addition, soil and litter are important influences controlling seed bank density in subalpine forests, and the results of structural equation modelling suggest that both disturbance and climate change can indirectly regulate the seed bank by changing the physicochemical properties of soil and litter. We conclude that increases in precipitation and temperature driven by climate change can buffer the negative effects of disturbances on the seed bank.

The role of TGF-ß1/Smad3 signaling pathway and oxidative stress in the inhibition of osteoblast mineralization by copper chloride.

To explore the relationship of oxidative stress and TGF-ß 1/Smad3 pathway in the inhibition of osteoblast mineralization by copper chloride (CuCl2), the osteoblasts were treated with CuCl2 (0, 50 µM, 100 µM, 150 µM CuCl2 5H2O) for 24 h. We found that Cu impaired the osteoblast structure, inhibited the glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities, alkaline phosphatase (ALP) content, mRNA expression of collagen I (COL-I), osteocalcin (OCN), insulin-like growth factor I (IGF-I), bone morphogenetic protein-2 (BMP-2), transforming growth factor ß1 (TGF-ß1) and core-binding factor α1 (Cbfα1), promoted the reactive oxygen species (ROS) production, inactivated the TGF-ß1/Smad3 pathway. It indicates that the inactivated TGF-ß1/Smad3 pathway leads to osteoblast impairment by CuCl2. It will contribute to clarify the influence of CuCl2 on the osteoblast mineralization.

Maternal transfer of antibodies specific for avian influenza viruses in captive whooper swans (Cygnus cygnus).

The transfer of maternal antibodies to offspring can effectively protect against avian influenza virus (AIV) infection during early life in chickens and can prevent AIV spread by decreasing the overall percentage of the avian population susceptible to this pathogen. Herein, we evaluated maternal antibody transfer dynamics in whooper swans (Cygnus cygnus), which represent an important AIV host species. In total, 57 eggs from 19 nests were collected to study the relationship between egg yolk AIV-specific antibody concentrations and factors including egg size, laying order, maternal serum AIV antibody titer, and maternal body condition. Overall, we found that AIV-specific antibodies were present in the serum of 63.2 % of surveyed female swans and were transferred to 50.8 % of analyzed eggs. We found maternal AIV-specific antibody concentration and body weight to be positively correlated with egg yolk AIV antibody concentration, whereas egg laying order was negatively correlated with yolk antibody titer. Overall, these findings maternal transfer of AIV-specific antibodies may function as a key mechanism governing the dynamics of AIV infection in swan populations.

Kaolin-Enhanced Superabsorbent Composites: Synthesis, Characterization and Swelling Behaviors.

One type of low-cost and eco-friendly organic‒inorganic superabsorbent composite (SAPC) was synthesized by free radical polymerization of acrylic acid (AA), starch (ST), sodium alginate (SA) and kaolin (KL) in aqueous solution. The structure and morphology of the SAPC were characterized by Fourier transform infrared spectrometer (FT-IR), scanning electron microscope (SEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The influence of different reaction conditions on water absorption of SAPC, i.e., SA and KL contents, AA neutralization degree (ND), potassium persulfate (KPS) and N, N'-methylenebisacrylamide (MBA) loading were systematically studied. Under the optimal synthesis conditions, very high water absorption of 1200 g/g was achieved. The swelling kinetic mechanism of SAPC was studied by pseudo-second order swelling kinetics model and Ritger‒Peppas model. The performances of SAPC under different environments were tested and results revealed that this new SAPC had excellent swelling capacity, high water retention, good salt tolerance in monovalent salt solution (NaCl solution) and good pH tolerance between 4 and 10.