农药制剂中助剂使用状况调研及风险分析

农药助剂在农药制剂生产中必不可少,是农药制剂产品的必要组成成分。农药助剂曾被误认为是对环境和人类健康无害的惰性物质,因此我国农药相关管理规定中没有对农药助剂的环境安全进行登记管理。通过对2010年和2011年拟申请登记的农药制剂剂型、助剂品种、作用、含量等基本数据的调查发现,农药助剂具有以下特征:1)调查农药品种368个,但出于商业机密考虑,仅51.6%的调查产品提供了农药助剂信息。2)提供助剂信息的190个农药制剂产品中使用的助剂品种数量为104种,其中玫瑰精、二甲苯、甲苯、环己酮、壬基酚等助剂或其代谢物具有健康风险。3)每种农药制剂中含有3~4种助剂成分,助剂含量占制剂量的1%~99%。     

Effect of sawdust addition and composting of feedstock on renewable energy and biochar production from pyrolysis of anaerobically digested pig manure

Pyrolysis experiments were conducted on the separated solid fraction of anaerobically digested pig manure (SADPM). The aim of these experiments was to investigate the influence of (1) sawdust addition and (2) composting the feedstock, on the products of pyrolysis and on the net energy yield from the pyrolysis process. Mixtures of SADPM and sawdust were made to give the following treatments; manure only, 4:1(w/w) and 3:2(w/w). These mixtures were pyrolized at 600 °C both before and after aerobic composting. The yields of the biochar, bio-liquid and gas were influenced by the addition of sawdust to the SADPM and by composting of the feedstock. With the addition of sawdust, biochar and gas higher heating values (HHV) increased, while bio-liquid HHV decreased. More than 70% of the original energy in the feedstock remained in the biochar, bio-liquid and gas after pyrolysis, increasing as the proportion of sawdust increased. The HHV of the biochar decreased, while the HHV of the bio-liquid increased, after the feedstocks were composted. The energy balance showed that increasing the rate of sawdust addition to SADPM resulted in an increased net energy yield. The addition of a composting stage increased the net energy yield for the manure only feedstock only. However, with increasing sawdust addition, composting of the feedstock reduced the net energy yield.     

Conducting polymer coated graphene oxide reinforced C–epoxy composites for enhanced electrical conduction

Enhanced electrical conductivities were achieved in C–epoxy composites by integrating them with conducting polymers (CPs), namely poly pyrrole (PPY), poly(3,4-ethylene dioxythiophene) (PEDOT) and graphene oxide (GO) enwrapped by CPs. By in-situ polymerization of pyrrole or 3,4-ethylenedioxythiophene (EDOT) in the presence of the GO (template), sodium bis(2-ethylhexyl) sulfosuccinate (structure directing agent), ferric chloride (oxidant), the electrically conductive sheets of GO enwrapped CPs were obtained. The formation of CP coating on GO was confirmed by Raman spectroscopy, scanning electron microscopy and thermo gravimetric analysis studies. Different wt% of CP and CP coated GO were added to the epoxy resin and this resin was used to prepare the 2D laminated C–epoxy composites by hand layup method. DC electrical conductivity of the prepared C–epoxy composites were analyzed using current–voltage (I–V) characteristics and impedance measurements. Typical results showed that CP coated GO, at 0.5 wt% addition to epoxy imparted highest DC electrical conductivity for C–epoxy composite.     

Removal of cyanide in aqueous solution by oxidation with hydrogen peroxide in presence of activated carbon prepared from olive stones

This work is dedicated to the removal of the very toxic free cyanide from aqueous solution by oxidation with hydrogen peroxide H₂O₂ in the presence of activated carbon prepared from olive stones. Effects of the initial molar ratio [H₂O₂]₀/[CN^?]₀, the initial cyanide concentration, the activated carbon concentration and the temperature on cyanide removal have been examined. The removal of free cyanide in absence of activated carbon showed very slow kinetics. The presence of activated carbon has increased the reaction rate showing thus a catalytic activity. The kinetics of cyanide removal has been found to be of pseudo-first-order with respect to cyanide and the rate constants have been determined for different values of the aforementioned parameters. The apparent activation energy has been determined from tests carried out at three different temperatures. It was found equal to 46.2 kJ/mol in the presence of activated carbon, which is about half of the 82.7 kJ/mol found for the oxidation in absence of the activated carbon.This process can be interesting for the cyanide removal from processed solutions because it does not use soluble metal catalyst and it consumes only hydrogen peroxide as chemical product.     

A hesitant fuzzy model of computational trust considering hesitancy,vagueness and uncertainty

The aim of this work is to introduce a trust model, which is highly consistent with the social nature of trust in computational domains. To this end, we propose a hesitant fuzzy multi-criteria decision making based computational trust model capable of taking into account the fundamental building blocks corresponding to the concept of trust. The proposed model is capable of considering the contextuality property of trust and the subjective priorities of the trustor regarding the chosen goal. This is due to viewing trust not as a single label or an integrated concept, but as a collection of trustworthiness facets that may form the trust decision in various contexts and toward different goals. The main benefit of the proposed model is the consideration of the hesitancy of recommenders and the trustor in the process of trust decision making which can create a more flexible mapping between the social and computational requirements of trust. This type of formulation also allows for taking into account the vagueness of the provided opinions. In addition to the vagueness of the provided opinions, the model is capable of considering the certainty of recommendations and its effect on the aggregation process of gathered opinions. In the proposed model, the taste of the recommenders and the similarity of opinions are also considered. This will allow the model to assign more weight to recommendations that have a similar taste compared to the trustor. Finally, taking into consideration the attitudes of the trustors toward change of personality that may occur for various entities in the environment is another advantage of the proposed model. A step-by-step illustrative example and the results of several experimental evaluations, which demonstrate the benefits of the proposed model, are also presented in this paper.     

Synthesis of ferronickel slag-based geopolymers

This paper deals with the synthesis of geopolymers utilizing ferronickel slag as raw material. The utilized slag is produced in the Greek plant LARCO during the pyrometallurgical treatment of laterites for the production of ferronickel, specifically at the step of the reductive smelting in electric arc furnaces. The performed work includes the optimization of the slag-based geopolymeric system through the study of the effect of the synthesis parameters on the mechanical properties of the produced materials. The structure of geopolymers was determined with X-ray diffractometry (XRD), Fourier-transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The obtained results showed that the ferronickel slag is an excellent raw material for the production of inorganic polymers using the geopolymerization technology. The materials produced under the optimum synthesis conditions were compact and rigid and presented high compressive strength (118 MPa), as well as extremely low water absorption (0.7–0.8%).     

Effect of the Y2O3–ZrO2 support composition on nickel catalyst evaluated in dry reforming of methane

Nickel catalysts with a load of 5 wt.% Ni, supported on pure ZrO₂ and ZrO₂ stabilized with 4 mol%, 8 mol% and 12 mol% of Y₂O₃, were prepared by the polymerization method. The samples were characterized by X-ray diffraction (XRD), temperature-programmed reduction with hydrogen (TPR-H₂), specific surface area (BET) and electronic paramagnetic resonance (EPR) and tested as catalysts for carbon dioxide reforming of methane. The XRD patterns showed the presence of the oxide precursor (NiO) and the tetragonal phase of a Y₂O₃–ZrO₂ solid solution. According to the TPR-H₂ analysis, the reduction of various NiO species was influenced by the composition of the support. Catalytic tests were conducted at 800 °C for 6 h, and the composition of the gaseous products and the catalytic conversion rate depended on the composition of the Y₂O₃–ZrO₂ solid solution and its influence on the supported NiO species. A direct relation was observed between the variation in the support, the nickel species supported on it and the performance in the catalytic tests.     

Conversion of recycled sawdust into high HHV and low NOx emission bio-char pellets using lignin and calcium hydroxide blended binders

Spruce wood sawdust (S), as biomass waste, could be utilized as a renewable fuel, but it suffers from its bulky, low energy density, high volatiles content and NO_x emission. This study investigated the possibility of conversion S into bio-char pellets (SC-Ps) as renewable and CO₂-neutral bio-fuel. Sawdust derived bio-char (SC) was produced through pyrolysis, and subsequently compressed into SC-Ps bonded by lignin (L) and hardened by Ca(OH)₂, NaOH, CaCl₂, CaO. The combustion characteristics of S and SC, the physical properties of SC-Ps including abrasive resistances (ARs), impact resistance index (IRI) and compress strengthens (CS) were evaluated. Results showed that the high heat value (HHV) of SC increased by 95% and its NO_x emission decreased due to the release of N-containing volatiles. Among these hardeners, addition of 5% Ca(OH)₂–10% L reduced the disruptive force created by uptake moisture and played an effect of hydration on hardening the bonds. In addition, the catalysis of hydroxide promoted the polymer chain growing into three-dimensional cross-linking that strengthened the bonds. Thus, the mechanical strengths of the SC-Ps bonded by Ca(OH)₂/L were sufficient for directly transportation and being charged into the blast furnace.     

Effects of torrefaction on the physiochemical properties of oil palm empty fruit bunches,mesocarp fiber and kernel shell

In this work, the effects of torrefaction on the physiochemical properties of empty fruit bunches (EFB), palm mesocarp fiber (PMF) and palm kernel shell (PKS) are investigated. The change of properties of these biomass residues such as CHNS mass fraction, gross calorific value (GCV), mass and energy yields and surface structure when subjected to torrefaction process are studied. In this work, these materials with particle size in the range of 355–500 μm are torrefied under light torrefaction conditions (200, 220 and 240 °C) and severe torrefaction conditions (260, 280 and 300 °C). TGA is used to monitor the mass loss during torrefaction while tube furnace is used to produce significant amount of products for chemical analyses. In general, the study reveals torrefaction process of palm oil biomass can be divided into two main stages through the observation on the mass loss distribution. The first stage is the dehydration process at the temperature below than 105 °C where the mass loss is in the range of 3–5%. In the second stage, the decomposition reaction takes place at temperature of 200–300 °C. Furthermore, the study reveals that carbon mass fraction and gross calorific value (GCV) increase with the increase of torrefaction temperature but the O/C ratio, hydrogen and oxygen mass fractions decrease for all biomass. Among the biomass, torrefied PKS has the highest carbon mass fraction of 55.6% when torrefied at 300 °C while PMF has the highest GCV of 23.73 MJ kg⁻¹ when torrefied at the same temperature. Both EFB and PMF produce lower mass fraction than PKS when subjected to same torrefaction temperature. In terms of energy yield, PKS produces 86–92% yield when torrefied at light to severe torrefaction conditions, until 280 °C. However, both EFB and PMF only produce 70–78% yield at light torrefaction conditions, until 240 °C. Overall, the mass loss of 45–55% of these biomasses is observed when subjected to torrefaction process. Moreover, SEM images reveal that torrefaction has more severe impact on surface structure of EFB and PMF than that of PKS especially under severe torrefaction conditions. The study concludes that the torrefaction process of these biomass has to be optimized based on the type of the biomass in order to offset the mass loss of these materials through the process and increase the energy value of the solid product.     

Characterization of CeO2–WO3 catalysts prepared by different methods for selective catalytic reduction of NOx with NH3

In this work, cerium–tungsten oxide catalysts were prepared by three methods: single step sol–gel (SG), impregnation (IM), and solid processing (SP). The catalysts were used for selective catalytic reduction (SCR) of NO_x with ammonia over a wide temperature range. The results indicated that the catalysts prepared by the SP and IM methods exhibited better SCR activity than that prepared via the SG method in 175–500 °C. The excellent activity can be attributed to larger surface area, higher surface concentrations of Ce and Ce^3 +, enhanced NO oxidization ability, and greater number of surface acid sites.