Partial least square modeling of hydrolysis: analyzing the impacts of pH and acetate

Introduction Environm ental and econom ic advantages highlight anaerobic digestion as a sustainable technology for solid w aste treatm ent (Edelm ann etal., 2000). A naerobic digestion could be described as four sequential steps: hydrolysis, acidogenesis, aceto- genesis and m ethanogenesis, am ong w hich the hydrolysis is recognized as the rate-lim iting step for particulate organic w aste (Jain et al., 1992; M ata-A lvarez, 2000). H ydrolysis occurs com m only together w ith the acidogenesi…     

Glutamicibacter nicotianae AT6: A new strain for the efficient biodegradation of tilmicosin

The degradation of tilmicosin (TLM),a semi-synthetic 16-membered macrolide antibiotic,has been receiving increasing attention.Conventionally,there are three tilmicosin degradation methods,and among them microbial degradation is considered the best due to its high efficiency,eco-friendliness,and low cost.Coincidently,we found a new strain,Glutamicibacter nicotianae sp.AT6,capable of degrading high-concentration TLM at 100 mg/L with a 97%removal efficiency.The role of tryptone was as well investig...     

Dechlorination of dichlorodiphenyltrichloroethane (DDT) by Fe/Pd bimetallic nanoparticles: Comparison with nZVI,degradation mechanism,and pathways

Frontiers of Environmental Science &; Engineering - Acclimation is the main method to enhance the productivity of microorganisms in environmental biotechnology, but it remains uncertain how...     

Sources appointment and health risks of PM2.5-bound trace elements in a coastal city of southeastern China

To gain a comprehensive understanding of sources and health risks of trace elements in an area of China with high population densities and low PM_2.5concentrations,15 trace elements (Al,K,Ca,Ti,V,Cr,Mn,Fe,Ni,Cu,Zn,As,Sn,Ba,Pb) in PM_2.5were monitored from December 2020 to November 2021 in a representative city,Xiamen.The concentrations of trace elements in Xiamen displayed an obvious seasonal variation and were dominated by K,Fe,Al,Ca and Zn.Based on Positive Matrix Factoriza...     

Role of sorbent surface functionalities and microporosity in 2,2’,4,4’-tetrabromodiphenyl ether sorption onto biochars

The study provides insight into the combined effect of sorbent surface functionalities and microporosity on2,2 ′,4,4 ′-tetrabromodiphenyl ether (BDE-47) sorption onto biochars. A series of biochars prepared underdifferent conditionswere used to test their sorption behaviorswith BDE-47. The extents of sorption behaviorswere parameterized in terms of the single-point adsorption equilibrium constant (Koc ) at three equilibrium concentration (C e ) levels (0.001Sw (solubility), 0.005Sw , and 0.05Sw )whichwasdetermined using the Freundlich model. To elucidate the concentration-dependentdominant mechanisms for BDE-47 sorption onto biochars, K ocwas correlatedwith four major parameters using multiple parameter linear analysis accompaniedwith significance testing. The results indicated that at low concentration (Ce = 0.001Sw ), the surface microporosity term,which represented a pore-filling mechanism, contributed significantly to this relationship,while as concentrationwas increased to higher levels, surface functionality related to surface adsorption began to take thedominant role,whichwas further confirmed by the results of Polanyi-based modeling. Given the above results, adual mode model based on Dubinin-Radushkevich andde Boer-Zwikker equationswas adopted to quantitatively assess the changes of significance of surface adsorption aswell as that of pore fillingwith sorption processdevelopment. In addition, UV spectra of four typical aromatic compoundswhich represented the key structural fragments of biochars before and after interactionswith BDE-47were analyzed todetermine the active functional groups and supply complementary evidence for thedominant interaction force for surface adsorption, based onwhich π-π electron-donor-acceptor interactionwas proposed to contribute greatly to surface adsorption.     

Effects of soil water and nitrogen availability on photosynthesis and water use efficiency of Robinia pseudoacacia seedlings

The efficient use of water and nitrogen (N) to promote growth and increase yield of fruit trees and crops is well studied.However,little is known about their effects on woody plants growing in arid and semiarid areas with limited water and N availability.To examine the effects of water and N supply on early growth and water use efficiency (WUE) of trees on dry soils,one-year-old seedlings of Robinia pseudoacacia were exposed to three soil water contents (non-limiting,medium drought,and severe drought) as well as to low and high N levels,for four months.Photosynthetic parameters,leaf instantaneous WUE (WUEi) and whole tree WUE (WUEb) were determined.Results showed that,independent of N levels,increasing soil water content enhanced the tree transpiration rate (Tr),stomatal conductance (Gs),intercellular CO2 concentration (Ci),maximum net assimilation rate (Amax),apparent quantum yield (AQY),the range of photosynthetically active radiation (PAR) due to both reduced light compensation point and enhanced light saturation point,and dark respiration rate (Rd),resulting in a higher net photosynthetic rate (Pn) and a significantly increased whole tree biomass.Consequently,WUEi and WUEb were reduced at low N,whereas WUE i was enhanced at high N levels.Irrespective of soil water availability,N supply enhanced Pn in association with an increase of Gs and Ci and a decrease of the stomatal limitation value (Ls),while Tr remained unchanged.Biomass and WUEi increased under non-limiting water conditions and medium drought,as well as WUEb under all water conditions;but under severe drought,WUEi and biomass were not affected by N application.In conclusion,increasing soil water availability improves photosynthetic capacity and biomass accumulation under low and high N levels,but its effects on WUE vary with soil N levels.N supply increased Pn and WUE,but under severe drought,N supply did not enhance WUEi and biomass.     

Evaluation of remediation process with soapberry derived saponin for removal of heavy metals from contaminated soils in Hai-Pu, Taiwan

The use of a biodegradable natural plant-based surfactant extracted from soapberry is proposed for the remediation of Ni, Cr and Mn from industrial soil site in Hai-Pu, Taiwan. Batch experiments were performed under variation of fundamental factors (saponin concentration, pH, and incubation time) for metal remediation. Removal of Ni and Mn were increased with increasing saponin concentration (0.015-0.150 g/L), whereas the removal of Cr was increased upto 0.075 g/L saponin. The Ni, Cr and Mn were removed significantly (p ≤q 0.05) at near to the neutral and slightly acidic (pH 5 to 8) conditions. Removal efficiency of Ni (99%) from the soil was found to be greater than that of Cr (73%) or Mn (25%) in the presence of saponin at a concentration of 0.150 g/L at pH 5. The removal percentage increased with incubation time where the removal of Ni was faster than that of Cr and Mn. The result indicates the feasibility of eco-friendly removal of heavy metal (Ni, Cr and Mn) from industrial soil by soil washing process in presence of plant derived saponin.     

Removal of tetracycline from water by Fe-Mn binary oxide

Significant concerns have been raised over the presence of antibiotics including tetracyclines in aquatic environments. A series of Fe-Mn binary oxide with different Fe:Mn molar ratios was synthesized by a simultaneous oxidation and coprecipitation process for TC removal. Results showed that Fe-Mn binary oxide had higher removal efficiency than that of hydrous iron oxide and hydrous manganese oxide, and that the oxide with a Fe:Mn molar ratio of 5:1 was the best in removal than other molar ratios. The tetracycline removal was highly pH dependent. The removal of tetracycline decreased with the increase of initial concentration, but the absolute removal quantity was more at high concentration. The presence of cations and anions such as Ca²⁺, Mg²⁺, CO₃^2- and SO₄^2- had no significant effect on the tetracycline removal in our experimental conditions, while SiO₃^2- and PO₄^3- had hindered the adsorption of tetracycline. The mechanism investigation found that tetracycline removal was mainly achieved by the replacement of surface hydroxyl groups by the tetracycline species and formation of surface complexes at the water/oxide interface. This primary study suggests that Fe-Mn binary oxide with a proper Fe:Mn molar ratio will be a very promising material for the removal of tetracycline from aqueous solutions.     

Tracking Cryptosporidium in urban wastewater treatment plants in a cold region: Occurrence,species and infectivity

• Cryptosporidium in WWTPs in a cold region was investigated in different seasons. • The overall removal efficiency of Cryptosporidium in WWTPs was over 84%. • The infectivity rate declined below 53% in effluents mainly due to disinfection. • The infectivity of Cryptosporidium increased with a seasonal drop in temperature. • Low temperature promotes binding protein retention and virulence genes expression. This study investigated the occurrence, species, infectivity and removal efficiency of Cryptosporidium spp. across typical wastewater treatment train. Samples from different process units were collected seasonally and synchronously from four wastewater treatment plants (WWTPs) in Northeastern China. Live Cryptosporidium oocysts were identified in most samples from both influent (97.50%) and effluent (90.00%) wastewaters of the four WWTPs, at an average density of 26.34 and 4.15 oocysts/L, respectively. The overall removal efficiency was 84.25%, and oocysts were mainly removed (62.01%) by the modified secondary sedimentation process. Ten Cryptosporidium species were identified in the effluent samples. C. andersoni, C. bovis, and C. ryanae were the three most prevalent species. Oocyst viability assays indicated no reduction of excystation rate during the primary and secondary wastewater treatments (varied in the range of 63.08%–68.50%), but the excystation rate declined to 52.21% in the effluent after disinfection. Notably, the Cryptosporidium oocysts showed higher infection intensity in the cold season (winter and spring) than that in summer and autumn. The influences of environmental temperature on virulence factors of Cryptosporidium were further examined. It was observed that more extracellular secretory proteins were bound on the oocyst surface and several virulence genes were expressed relatively strongly at low temperatures, both of which could facilitate oocyst adhesion, invasion, and host immune evasion. This research is of considerable interest since it serves as an important step towards more accurate panoramic recognition of Cryptosporidium risk reduction in WWTPs, and especially highlights the potential health risk associated with Cryptosporidium in cold regions/seasons.     

Study on Economic growth,Urbanization and Sustainable Utilization of Cultivated Land in China

By means of the dynamic regression model, this paper analyzes the relationships among economic growth, urbanization and changes of cultivated land in China, finds that the ratio of cultivated land occupied by economic growth is decreasing with social and economic growth. And, based on that, some policy suggestions on how to promote the sustainable use of cultivated land in China are put forward.