Search

In this study, a novel nanoadsorbent (Fe3O4 SiO2-GSH MNPs) based on iron oxide magnetic nanoparticles (Fe3O4 MNPs), coated with SiO2 shells and further modified via reduced glutathione (GSH), was successfully synthesized and applied for Pb(II) removal. Characterization results suggested that the prepared nanoadsorbents were in uniform size and provided numerous adsorption sites for Pb(II), nanoparticles could be convenient separated with the help of external magnet due to their superparamagnetism. Adsorption results showed that the prepared nanoadsorbents exhibited excellent adsorption capacity, even at a large range of Pb(II) concentrations and ionic strength scope. Kinetic of the Pb(II) adsorption was found to follow pseudo-second-order rate equation. Adsorption isotherm data was best fitted to Freundlich model (R2 = 0.9888–0.9959), and the maximal Pb(II) adsorption capacities were calculated as 298.87, 332.44 and 357.37 mg g−1, at 298, 303 and 308 K, respectively. Based on the efficient Pb(II) adsorption ability and reusability studies, Fe3O4 SiO2-GSH MNPs were confirmed to be a promising candidate for Pb(II) removal from industrial effluents.

The objective of this study was to investigate the adsorption behavior and the relative distribution of Cd

The effect ofPhanerochaete chrysosporium(Pc) on the characteristics of humic substances (HS) was investigated during composting of agricultural wastes. The dynamic changes of HS, fulvic acid (FA), humic acid (HA) and the humification index (HI) were monitored during a 60-day composting. The results showed that the formation of FA was not obviously influenced, while HA formation was improved by the inoculum ofPc. During the composting process, HI increased from 0.28, 0.29 to 2.23 and 3.17 in the control and the treatment, respectively. This result indicated thatPccould significantly enhance the degree of HS aromatization (PPcto the formation of HS during composting and provide some useful information for the development of efficient methods to increase the content of HS in the composting.

Immobilized microbe technologies are expected to be effectively used in wastewater treatment. Removal of heavy-metals from wastewater by immobilized Phanerochaete chrysosporium (Pc) with Ca-alginate and iron oxide magnetic nanoparticles (MNPs) was studied. The results showed that a biosorbent as Pc immobilized by Ca-alginate and iron oxide magnetic nanoparticles was successfully developed. And the iron oxide magnetic nanoparticles played an important role in the increase of biosorption capacity of Pc. Energy dispersive spectrometer (EDS) analysis confirmed that metal ions adsorbed to the surface of the biosorbents were partly transmitted to the interior of biosorbents, mainly embedded with iron oxide nanoparticles and Ca-alginate. Moreover, it was found that MNPs-Ca-alginate immobilized Pc showed a good affinity to various heavy metals, such as Pb(II), Zn(II), Cd(II) or Mg(II) and so on. The results proved the high efficiency of the biosorbents for heavy-metal removal and its potential application in the treatment of metal-containing wastewater.

A novel adsorbent, iron oxide magnetic nanoparticles and Ca-alginate immobilized Phanerochaete chrysosporium , was prepared for removal of Pb(II) ions. Confirmation of the experimental data indicated the pseudo-second-order reaction of the prepared adsorbents. Langmuir isotherm was found to be applicable in terms of relatively high correlation coefficients, which indicated that the adsorption between Pb(II) and the adsorbent was favorable. The thermodynamic analysis showed that the adsorption of Pb(II) was spontaneous and endothermic under the experimental conditions. The adsorption–desorption studies indicated that the prepared adsorbent kept its adsorption efficiencies constant over 5 cycles, maintained about 90%. All the results illustrated that MNPs–Ca-alginate immobilized P. Chrysosporium was a very attractive adsorbent for efficient Pb(II) removal from contaminated aqueous solution.

Nowadays there is a continuously increasing worldwide concern for the development of wastewater treatment technologies. The utilization of iron oxide nanomaterials has received much attention due to their unique properties, such as extremely small size, high surface-area-to-volume ratio, surface modifiability, excellent magnetic properties and great biocompatibility. A range of environmental clean-up technologies have been proposed in wastewater treatment which applied iron oxide nanomaterials as nanosorbents and photocatalysts. Moreover, iron oxide based immobilization technology for enhanced removal efficiency tends to be an innovative research point. This review outlined the latest applications of iron oxide nanomaterials in wastewater treatment, and gaps which limited their large-scale field applications. The outlook for potential applications and further challenges, as well as the likely fate of nanomaterials discharged to the environment were discussed.

The transformation behaviors of Pb fractions during composting of Pb-polluted waste without inoculants and with the inoculants of Phanerochaete chrysosporium were studied. Results show that the active Pb ions with high toxicity and transferability are transformed into the inactive Pb with low toxicity and transferability, confirming that Pb ions can be efficiently immobilized during composting without or with the inoculants. The soluble-exchangeable Pb in composting without inoculants reaches 49.0 mg/kg at day 60, while that with the inoculants is reduced to 0 mg/kg dry mass compost. The higher contents of organic-bound Pb (59.0 mg/kg) and residual Pb (69.2 mg/kg) with low toxicity are found after 60-day composting with inoculants, compared with those without inoculants. The above data indicate the better immobilization effect of Pb and the greater alleviation of Pb hazards in composting with the inoculants of Phanerochaete chrysosporium than without inoculants, which may be due to the more microbial biomass and the higher pH value in composting of Pb-polluted waste with inoculants.

The lignocellulolytic microorganism, Phanerochaete chrysosporium, was inoculated during different phases of agricultural wastes composting, and its effect on compost maturity was studied. In the three runs, the decrease in C/N ratio and increases in germination index and humification indices (humification ratio, humification index, percentage of humic acids and degree of polymerisation) were found. Furthermore, the different effects of inoculation during different phases on the compost maturity could be observed by using ANOVA. When inoculated during the second fermentation phase, P. chrysosporium induced significant changes on all parameters of compost maturity except C/N ratio, whereas it did not produce an obvious change on these parameters when inoculated during the first fermentation phase.

The laccase activities of Penicillium simplicissimum H5 during solid-state fermentation with rice straw were studied. Degradation of lignocellulose was also followed. Results showed that all supplemental carbon sources inhibited the laccase activity in different degrees, while suitable concentrations of supplemental nitrogen sources remarkably enhanced the laccase activity. The enhancement of activity by the ordinary laccase inducers 2, 2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) and xylidine was not observed in this study. Lignocellulose degradation was improved when laccase activity was relatively low, suggesting a polymerizing function of laccase in lignin degradation by P. simplicissimum.

Penicillium simplicissimum(Oudem.) Thomrn BGA can secrete lignocellulolytic enzymes, among these enzymes the highest activities of hemicellulase, cellulase, lignin peroxidase (Lip), manganese peroxidase (Mnp) and laccase are 146.82 Iu.g-1, 2.78 U.g-1, 47.97 U.g-1, 34.56 U.g-1 and 17.94 U.g-1 respectively. According to the results and the statistical analysis of SPSS, the ability of secreting lignocellulolytic enzymes by Penicillium simplicissimum significantly correlated with the structure of lignocellulose, and the biodegradation of lignocellulose was probably a kind of synergistic effect of several lignocellulolytic enzymes. In the solid-state fermentation of 30 days, the hemicellulose content has a significantly negative correlation with the fermentation days(r = -0.946, P0.01), there was also a significantly negative correlation between the cellulose-biodegradation and the lignin-biodegradation (r = -0.818, P0.05). As unselected enzymes, Lip and Mnp can degrade hemicellulose and cellulose corporately when biodegrades lignin. The significant correlation is showed between Lip, Mnp and cellulose (correlation parameters are r = 0. 922, P0.01; r = 0.807, P0.05 respectively). In addition, the biosorption is found to have a very important effect in the removal of liquid alkali lignin by Penicillium simplicissimum. Key words:Penicillium simplicissimum; lignocellulolytic enzymes; biodegradation; biosorption; synergistic effect

The production of oxalate at different initial Pb(2+) concentrations during solid-state fermentation of straw with Phanerochaete chrysosporium was investigated. It was found that the maximal peak value of oxalate concentration (22.84 mM) was detected at the initial Pb(2+) concentration of 200 mg kg(-1) dry straw, while the minimum (15.89 mM) at the concentration of 600 mg Pb(2+)kg(-1) dry straw, and at moderate concentration of Pb(2+) the capability of oxalic acid secretion was enhanced. In addition, it was also found that more oxalic acid accumulation went together with better Pb(2+) passivation effect and higher manganese peroxidase (MnP) activity. The present findings will improve the understandings of the interactions of heavy metals with white-rot fungi and the role of oxalate in lignin degradation system, which could provide useful references for more efficient treatment of Pb-contaminated lignocellulosic waste.

To understand the characteristics of ligninolytic enzymes sorption and transport in different compost substances, ligninolytic enzymes adsorption on soil, vegetable leaf, rice straw and chaff was comparatively studied through batch jar tests and relevant kinetics and isotherm equilibrium were discussed as well as a column experiment was performed to study the process of transport. The results showed that the sorption efficiency was depended on the sorts of substances. The adsorptive capacities of soil, vegetable leaf, rice straw and chaff to lignin peroxidase (LiP) were 1.22 U x g(-1), 1.27 U x g(-1), 1.13 U x g(-1), 1.22 U x g(-1) and to manganese peroxidase (MnP) were 5.09 U x g(-1), 4.88 U x g(-1), 4.43 U x g(-1), 3.95 U x g(-1), respectively. Comparing the kinetic models of LiP and MnP adsorption, the pseudo-second-order reaction model (R2 0.973-0.999 7) was the best of the models. Elovich equation was a bit better than pseudo-first-order kinetic which was the worst. The equilibrium data could be fitted well with Langmuir model while it could not satisfied with Freundlich model. The adsorptive saturation of soil, vegetable leaf, rice straw and chaff to LiP were 1.23 U x g(-1), 1.30 U x g(-1), 1.17 U x g(-1), 1.14 U x g(-1) and to MnP were 5.70 U x g(-1), 5.19 U x g(-1), 4.73 U x g(-1), 4.14 U x g(-1). LiP and MnP had good transport capability in straw and chaff to move to the deepest layer of 10 mL while remained in the superficial layers in soil and vegetable leaf.

The effects of enzymes on organic material degradation and microbial communities metabolic profiles during composting process were studied using Biolog method, and together with cluster analysis and PCA. The results showed that, adding the enzyme solution in the composting could increase the degradation rate of organic material by 4.90%. The microbial community metabolic results of cluster analysis showed that when the enzyme solution was added into the compost, the carbon metabolic capability of intermediate metabolite was improved. The results of PCA indicated that when the enzyme solution was added, microbial communities enhanced the metabolic capability of miscellaneous, polymers, amino acids and amides carbon substrates, which results in the efficient degradation of organic substance. In addition, cluster analysis of each composting phase showed that the effects of the enzymes solution on microbial community metabolism were mainly observed on 6 d and 30 d, which promoted the composting process.

Solid-state fermentation system of rice straw was established with the inoculation of soil microorganism and Phanerochaete chrysosporium. Microbial biomass and community structure were investigated using the phospholipid fatty acid (PLFA) technique, and the changes of lignocellulose's degradation rate were also detected during the process. The experimental results show that lignocellulose degradation rate reaches 44% after fermentation. When the total amount of phospholipid fatty acid is separated into indicator phospholipid fatty acids for different groups of microorganisms, these groups show different patterns during the process. Contents of PLFA in gram-positive bacteria, gram-negative and fungi reach their peak value on the sixth day. Gram-positive bacteria have lower contents. The PLFA content ratio of fungi and bacteria is 0.2 - 0.5, so fungi are the main community decomposing lignocellulose. Principal component analysis of the PLFA data show that 18 carbon unsaturated fatty acids are the major fatty acids at the end of the process, which is consistent with the results of indicator phospholipid fatty acids and lignocellulose's degradation rates, so PLFA technique is able to fairly well detect the changes of microbial biomass and community structure in solid-state fermentation system of rice straw.

In the experiment four parallel beakers A, B, C,D were adopted, among which A was without any inoculum, B was added with the inocula of immobilized Phanerochaete chrysosporium, C was inoculated with non-immobilized Phanerochaete chrysosporium, and D was only with pentachlorophenol (PCP)-contaminated soils open to air. By contrastive analyses, the feasibility of applying composting to the bioremediation of the PCP-contaminated soil was discussed. It can be seen from the experimental results that composting with inocula was better than that without innoculation and after 60d composting, more than 94% PCP in the compost was degraded; meanwhile the effect by immobilized fungi was better than that by nonimmobilized one. From the experimental data it shows that the PCP degradation achieved 50% on 9d by immobilized fungi. What's more, shown by indicators of germination index, volatile solids, microbial carbon activity and other factors, the compost were mature and of no hazard to plant at the end, which provided the benign environment for the Phanerochaete chrysosporium to degrade the PCP so that the bioremediation and composting could be combined together.

Simulative lead polluted wastes which containing unpolluted soil, household waste, straw, bran and lead nitrate were prepared. Inoculation of white-rot fungi and uninoculation in composting of lead-contaminated waste were studied. Change of chemical factor, biological parameter and biological toxicity analyses with time during the composting process were determined to study effect of heavy metal on composting process and probability of application of white-rot fungi in composting of metal-contaminated waste. The results show the composting of lead-contaminated waste inoculated white-rot fungi could be successfully processed, which lead to the reduction of the bioavailability of Pb in compost and alleviate the potential harm from heavy metal. Under this composting process, for the final compost, pH, water-soluble organic carbon/nitrogen, volatile solid, lignin and coarse fibre remained reached 7.9, 4.01, 36.1%, 22.4g, 30.1g, respectively. In addition, 63.38% of Pb in residual fraction and 0% of Pb in soluble-exchangeable fraction were found in final compost, and the germination index of final compost reached 121%.

The three kinds of sorbents of 0.18% KH2PO4, 0.06% KH2PO4 + 15% sawdust mixture and 30% sawdust are added separately into composting to investigate their adsorption effect on ammonia. The experiment results exhibite that all the sorbents can restrain ammonia volatilizing. But sorption of 0.18% KH2PO4 sorbnet was best of all, one of 0.06% KH2PO4 + 15% sawdust mixture sorbent was secondly, one of 30% sawdust sorbent was thirdly. The total nitrogen loss ratios were separately reduced 25%, 23% and 17% after adding the three kinds of sorbents into composting. However, excessive KH2PO4 would produce negative influence on compost property, such as pH value being lessened, microorganism activity being reduced, and finally resulting in the reduction of biodegradation ratio of organic matter also. Comparing with it, there were not these problems as 0.06% KH2PO4 + 15% sawdust mixture being sorbent. The mixture sorbent not only produced finer adsorption effect on ammonia, but also made biodegradation ratio of organic matter to be promoted 7%.