Effective management and beneficial utilization of liquid digestate is becoming a bottleneck of anaerobic digestion. Electrodialysis exhibits considerable potential in liquid digestate valorization; however, the process is typically challenged by severe membrane fouling due to high organic matter content. In the present study, a bench-scale electrodialysis was carried out to treat fresh and mature digestate with an aim of investigating the behavior of dissolved organic matter (DOM) during electrodialysis using ultrahigh-resolution mass spectrometry. Organics that were easily transported across the ion-exchange membrane (IEM) had relatively high O/C ratios (0.208–0.414) contributed from carboxyls, as well as relatively low H/C ratios (1.15–1.55) and high aromatic indexes (0.257–0.504) contributed from the benzene rings. Chemical cleaning with HCl and NaOH exhibited a cleaning effect on 66%–69% richness of DOM and completely removed 33%–38% richness of foulants via deprotonation or protonation effects, whereas 36%–45% richness of DOM, which had significantly higher aromatic indices, could not be completely removed by chemical cleaning due to their high hydrophobic affinity for the polymer matrix of IEM. The speculated fouling mechanisms included electrostatic interactions, hydrophobic interactions, hydrogen bonding, and geometrical exclusion. The results of the present study could enhance our understanding of DOM behavior during electrodialysis at the molecular level and, in turn, provide insights into the mitigation and prevention of membrane fouling in electrodialysis for the treatment of other organic-rich wastewaters.
The papermaking performance of the mixed pulp containing several hardwood BCTMP and wood bleached kraft pulp was studied.It was found that,under the similar solid content,the wet web strength is affected little when 10% BCTMP is substituted for 10% bleached hardwood KP.When 10% aspen BCTMP(HT) is substituted for 10% bleached hardwood KP,the handsheet has similar bulk,higher tear index and lower other physical strengths compared to the 100% wood bleached KP handsheet.When 10% aspen BCTMP(HB) or birch BCTMP is substituted for 10%bleached hardwood KP,the handsheet has higher bulk,similar tear index and lower other physical strengths.The brightness of the paper reduces when 10% aspen BCTMP(HB) is used as the substitution,but the whitening efficiency of OBA is affected little.
In order to satisfy the requirement of equipment layout of the decontamination station, using SLP theory and method to transform the decontamination objects and decontaminant into logistics objects, and the internal equipment layout of the decontamination station is designed.First, determine the decontamination process.Then, divide decontamination operation units and analyze closeness of the logistics and non-logistics relationship between the units to generate a comprehensive relationship diagram of the operation units.Finally, two layout schemes are designed considering the actual constraints of the decontamination operation, and the evaluation method was carried out by using the hierarchical weighted factor comparison evaluation method to obtain the optimal scheme.
Experiments were made on the effect of solid inert mediums on the coal dust explosion pressure and the pressure rise rate. Main factors affecting the function of solid inert mediums were given. Three samples of coal dust and limestone dust were selected from Canada and China, and their composition and particle size were separately analyzed and measured. A 20-liter spherical vessel was used to test explosion pressure and the rising rate. By changing concentration of limestone dust, the different maximum explosion pressure Pmax and the maximum rate of pressure rise(dp/dt)max were acquired. The experimental results show that limestone can be used to reduce the explosion pressure and the pressure rising rate of coal dust explosion. Besides, along with the reduction of the particle size of the coal dusts, more limestone dust is needed to get the same explosion suppression result.
There are a certain amount of fibers in paper mill sludge,including the short fibers and fines,which can be reused.Collagen fiber is a compound with high bond energy,and collagen fiber contains many polar groups,which can be well combined with hydrogen bond.In this paper,manufacture of corrugating medium with paper mill sludge and collagen fibers as raw material was studied.The results found that the ring crash index of the corrugating medium can meet the national product standard requirement.
Nutritive and functional composition in different parts(body wall,intestine and spawn) of Stichopus japonicus were investigated in this paper.The results were shown as follows: Stichopus japonicus was of high protein and the content of protein in the intestine and spawn were higher than those in body wall;Cu,Fe,Mn,Zn and other metal elements were abundant,which were more likely enrichment in the intestine;the content of δ-VE was high,especially in the intestine;the percentage content of acid mucopolysaccharide in the body wall was high and the content was 5.03%;composition of amino acids was complete,and free amino acids(FAA) were rich.Hydroxyproline which was the basis of collagen protein accounted for 4.20% in the body wall;there were 23 kinds of fatty acids were detected and it was found that the essential fatty acids content was high,especially the content of C20∶5 n3(EPA) was 16.06% in the intestine.In conclusion,Stichopus japonicus was of high nutrition value and some officinal value.
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