Adsorption of trivalent chromium from dilute solution by conifer leaves

Summary  Chromium(III), Cr(III) adsorption capacities of the leaves of 34 conifer species were examined. Among these, Ginkgo biloba, Taxus cuspidata, Cephalotaxus harringtonia var. nana, and Taxodiaceae and Cupressaceae spp. showed large capacities to adsorb Cr(III). The adsorption capacities of conifer leaves for Cr(III) (3.12–5.09 mg Cr g⁻¹ adsorbent) compared favorably with those of commercial activated carbons (1.23–2.75 mg g⁻¹). Factors affecting Cr(III) adsorption were studied using G. biloba leaves. The factors included solution pH, contact time, temperature, and the initial concentration of Cr(III). The amount of Cr(III) adsorbed on the adsorbent increased steadily with increasing pH in a pH range from 2 to 5, with increasing contact time, and with increasing temperature ranging 20 to 40 °C. The Cr(III) adsorption was also affected by the initial concentration of Cr(III) in the solution.  A linear relationship was observed between the amount of Cr(III) adsorbed and the equilibrium concentration of Cr(III) in the solution when graphed logarithmically. The maximum capacity of G. biloba leaves was 27.5 mg Cr g⁻¹ adsorbent by column experiments. Received 13 January 1998     

Removal of Cr(VI) from aqueous solutions by larch bark

The ability of larch (Larix leptolepis Gold.) bark to remove Cr(VI) from dilute aqueous solutions was investigated. The research parameters included the solution pH, contact time, temperature and initial concentration of Cr(VI) in solution. Of the parameters studied, the solution pH was found to be the most crucial. The Cr(VI) removal decreased steadily throughout the pH range studied (pH 2–6), while the Cr adsorption peaked at pH 3. Because the chemical reduction of Cr(VI) to trivalent state occurred to lesser extents even in strong acidic media, the Cr(VI) removal was mainly governed by physico-chemical adsorption. The positive value of the heat adsorption (ΔH ⁰) indicates the endothermic nature of the Cr(VI) adsorption. The relatively slow rate and irreversible nature of the adsorption as well as the order of the magnitude of the heat adsorption value suggest that the adsorption is of a chemical type. The adsorption data obtained from the equilibrium experiments were well fitted to both the Langmuir and Freundlich isotherms.     

Removal of heavy metal ions from solutions by coniferous barks

Summary The abilities of 15 coniferous barks for removing toxic heavy metal ions were investigated. The barks considerably varied in the adsorption ability to each metal ion. Of the barks tested, high adsorption ability for heavy metal ions was found inPicea abies (Norway spruce). Equilibrium experiments usingP. jezoensis (Yezo spruce) bark showed that the adsorption of Cd²⁺ was greatly affected by the pH of solution and the initial Cd²⁺ concentration in solution. The adsorption of Cd²⁺ byP. jezoensis bark followed Freundlich isotherm in the concentration range 10–330 mg Cd²⁺/L. The continuous column experiments usingP. jezoensis bark indicated that the packing had retained 10.1–14.2 mg Cd²⁺/g adsorbent until the column broke through.     

Stem-rot damage and the progress of causal fungi in old-aged Japanese larch trees at the foot of Mt. Fuji

Damage caused by stem-rot and the progress of the causal fungi in old-aged Japanese larch (Larix kaempferi (Lamb.) Carr.) was investigated at the foot of Mt. Fuji. Stem-rot was found in 75% of 108 trees investigated, and volume of rot was 6% of the total wood volume in the forest investigated. Stem-rot damage was much greater than the damage by butt-rot.Stereum sanguinolentum (Alb. and Schw. ex Fr.) Fr. infected larch trees at the greatest incidence (49.4%). However,Porodaedalea chrysoloma (Fr.) Imaz. caused the most volume loss to the trees.S. sanguinolentum infected larch stems mainly through stem wounds, and decay caused by the fungus progressed 9.75×10² cm³/year on average.P. chrysoloma infected larch stems mainly through dead branches and wounds, and the average rate of decay progress for the fungus was 2.74×10³ cm³/year.     

Adsorption of metal and uranyl ions onto amidoximated Pinus densiflora bark

Pine (Pinus densiflora) bark was chemically modified by grafting with acrylonitrile (AN) through Fenton reaction and conversion of the cyano group to an amidoxime group by reaction with hydroxylamine. Treatments of pine bark with 160 mM H₂O₂ at 40°C yielded ~70% grafting in 6-h reaction. After alkali hydrolysis of amidoximated pine bark (AOPB), its adsorption capacity (q _e) for copper ions was largely increased from 0.5 to 1.8 mmol/g. Adsorption of the hydrolyzed AOPB (HAOPB) followed the pseudo-second-order kinetic model. Among the metal ions tested, the order of adsorption capacity (q _e) predicted by the kinetic model at equilibrium time was Hg²⁺ > UO₂ ²⁺ > Cd²⁺ > Cu²⁺ > Zn²⁺ > Ni²⁺. The adsorption process was pH-dependent, and the adsorption equilibrium was observed in the pH range of 6–7 for all the metal ions. Even though pine bark is a good adsorbent for Hg²⁺ and UO₂ ²⁺ ions, it had a poor affinity for the other ions tested. It was obviously found that HAOPB had very high adsorption abilities for heavy metal and uranyl ions.     

Sorption of Cr(VI) on the wood of Japanese larch treated with concentrated sulfuric acid

A carbonaceous sorbent was prepared from the wood of Japanese larch (Larix leptolepis) by dehydration with concentrated sulfuric acid in a 69% yield. The abilities of the sorbent to remove Cr(VI) from aqueous solutions were investigated. Research parameters included the initial solution pH, temperature, and initial concentration of Cr(VI) in solution. The removal of Cr(VI) was highly solution pH dependent and was mainly governed by physicochemical sorption under weak acidic conditions. The equilibrium data fit well in the Langmuir isotherm model. The Langmuir constants were calculated at different temperatures, and the sorption capacity increased with rising temperature, indicating the endothermic nature of the Cr(VI) sorption onto the sorbent. The desorption experiments suggest that the Cr(VI) sorption is generally irreversible, owing to strong interaction of HCrO ₄ ⁻ with the active sites of the sorbent.     

Characteristics of reproductive biology forLarix originating in Japan

The paper summarized the life cycle, environmental features and distributions ofLarix origination in Japan. The time of blooming and fruiting and the ways of cone collection and seeds storage were introduced. The treating methods of seeds germination and the sowing time for both Japanese larch (Larix kaempferi Carr) and Dahurian larch (Larix gmelinii var.japonica Pilger) were discussed. Responsible Editor: Zhu Hong     

Dynamic feature of flavonoids content in different organs of larch （Larix gmelinii）

Flavonoids in plants is very important in its ecological role and economic value. The dynamic features of flavonoids content in different organs of larch (Larix gmelinii) at different light and temperature conditions were investigated in this study. Results showed that the order of flavonoids content in different organs from high to low was 7.78% (stem bark)>2.79% (leaves) >1.72% (branches) >1.19% (stem xylem)and different organs had a great seasonal variation in flavonoids content, but the change of flavonoids content at different temperature was not obvious in different organs., The content of flavonoids in barck had, a positive correlation with temperature (R ²=0.75), but that in other organs had slight variation with the change of temperature. For all the tested organs, the flavonoids content in summer and autumn was approximately 3–4 times higher than in spring and winter. This is attributed to the great stress from environmental physical variables such as UV radiation, high temperature that induce the accumulation of flavonoids. The flavonoid content of sun leaves was evidently higher than that of shade leaves, and leaves at upper part of canopy had a higher flavonoids content compared with that at other parts. This result indicates that sun radiation could improve flavonoids production in leaves (R ²=0.76). The flavonoids may actively evolve in plant defenses to environmental stress, protecting larch from the damage of high temperature and radiation, and its main function is different in different organs. Foundation item: This paper is supported by the National Natural Science Foundation of China (30300271) and the Key Project of Chinese Ministry of Education (104191). Biography: WANG Wen-jie (1974-), male, Lecturer in Key Laboratory of Forest Plant Ecology, Northeast Forestry University, Harbin 150040, P. R. China. Responsible editor: Zhu Hong     

Determination of reaction rate parameters for the acid copper chromate fixation reactions on oak (Quercus castaneifolia C. A. Mey) sapwood

Acid copper chromate fixation reactions on oak (Quercus castaneifolia C. A. Mey) sapwood were characterized by at least two distinguished reaction periods which differ in their kinetic behavior, particularly reaction rate. In this research, chemical rate equation parameters were studied in detail as a function of chromium fixation time. Theoretically, the kinetic data were distinguished between the adsorption and reduction reactions and consequently, the rate parameters were determined for each stage distinctly. The obtained results showed that at the investigated thermal range (25–33°C), almost for every 3°C increase in temperature the reaction duration has decreased 20.4?min for the first reaction period and 78?min for the second reaction period. Besides that, in all sample replications, up to 58.3% of hydrogen ions function at the reduction reactions of the initial period, demonstrating that acidity (H⁺ ions) has a major effect on reaction rate constant. Accordingly, adsorption reactions of the hexavalent chromium at the starting point follow a pseudo-first-order kinetic reaction. Different to the adsorption reaction the Cr^VI reduction reaction is exothermic with a measured exothermal energy of 48.2?kJ/mol.     

的吸附

以胶原纤维为基质,通过交联剂将黑荆树单宁、落叶松单宁和毛杨梅单宁固化在胶原纤维上制备吸附材料.实验表明,3种固化单宁对Cu2+的吸附平衡均符合Freundlich方程,其吸附容量大小顺序为固化毛杨梅单宁>固化黑荆树单宁>固化落叶松单宁.进一步研究了固化黑荆树单宁的吸附动力学、吸附柱动力学,以及温度、pH值等对吸附平衡的影响.结果表明,温度对吸附平衡的影响不明显,但pH值对吸附平衡有较大影响,在适当范围内提高pH值,会增加平衡吸附量;吸附动力学可用拟二级速度方程来描述,当吸附温度≥318 K时,由拟二级速度方程计算所得到的平衡吸附量与实测的平衡吸附量非常吻合.固化单宁具有良好的柱动力学特性,吸附柱极易再生并且能循环使用,吸附过程极有可能是在材料的表面进行.     

Estimated amount of carbon accumulation of hybrid larch in three 31-year-old progeny test plantations

Hybrids generated by crossing Kuril larch (Larix gmelinii var. japonica) and Japanese larch (L. kaempferi) are expected to have high carbon accumulation ability because of fast growth and high wood density in Hokkaido, Japan. We estimated the amount of carbon accumulation of the hybrid larch in three progeny test plantations consisting of 21 full-sib families and compared the results to the carbon accumulation of open-pollinated progenies of Japanese larch plus-trees (improved Japanese larch). Gene-environment interactions were not observed for tree height and diameter at breast height but were seen for wood density (area-weighted density, AWD). The amount of carbon accumulated per unit area (C_stand) positively correlated with the stand volume. The AWD did not correlate with the C _stand; therefore, families with high wood density can be selected independent of the C _stand. The C _stand of the best full-sib family, female parent half-sib family, and male parent half-sib family at three sites were 106.1, 84.6, and 93.2 Cton·ha⁻¹, respectively. All these values exceed the mean for the improved Japanese larch, which has a C _stand value of 82.5 Cton·ha⁻¹.     

立地条件对长白落叶松气体交换特性的影响

采用LI－6400便携式光合测定系统测定了黑龙江省佳木斯市孟家岗林场不同立地条件、不同龄组长白落叶松的气体交换参数。结果表明,饱和光照强度下长白落叶松的气孔导度、蒸腾速率和水分利用效率受针叶朝向（阳生叶和阴生叶）、立地条件和林龄的影响而表现出不同。除幼龄林立地指数为12的阳生叶和阴生叶气孔导度、蒸腾速率和水分利用效率,幼龄林立地指数为18的阳生叶和阴生叶气孔导度和蒸腾速率,近熟林立地指数为17的阳生叶和阴生叶蒸腾速率存在显著差异外,其余所有林龄相同立地指数的阳生叶和阴生叶气孔导度、蒸腾速率和水分利用效率均无显著差异。近熟林的阳生叶和阴生叶气孔导度,中龄林和近熟林的阳生叶水分利用效率受立地条件的影响均不显著;幼龄林阳生叶和阴生叶的水分利用效率,近熟林阳生叶和阴生叶的蒸腾速率均随着立地指数的增加表现出显著升高的趋势;幼龄林和中龄林阳生叶和阴生叶的气孔导度和蒸腾速率,中龄林和近熟林的阴生叶水分利用效率均随着立地指数的增加表现出显著降低的趋势。饱和光照强度下阳生叶和阴生叶气孔导度和蒸腾速率受林龄的影响显著,而水分利用效率受林龄的影响不显著。     

原位固化落叶松单宁对Cr( Ⅵ )的氧化还原吸附

研究了树皮原位固化落叶松单宁对水溶液中Cr6 的吸附特性。结果表明,Cr6 在该吸附剂上的吸附属于氧化还原吸附,即Cr6 首先被还原为Cr3 ,然后被吸附。当温度为303 K、pH值2.0、Cr6 的初始质量浓度为297.3 mg/L时,该吸附材料对Cr6 的平衡吸附量为183.6 mg/g,随着温度的升高平衡吸附量增加。pH值对平衡吸附量的影响较大,静态吸附时,产生最大吸附容量的pH值为2.0,这是由于该pH值条件有利于Cr6 的还原反应。该吸附材料对Cr6 的吸附平衡符合Freundlich方程;吸附动力学可以用拟二级速度方程来描述。固定床吸附实验表明,当原料液的Cr6 质量浓度为232.4 mg/L,流出液的体积约为120个床层体积时达到穿透点。     

Distribution of the larch brown rust caused byTriphragmiopsis laricinum (Uredinales) in Russian Far East

The larch brown rust caused byTriphragmiopsis laricinum was found onLarix cajandri in Primorsky Territory, Russia. This was a new host and locality record for the pathogen. Preliminary survey of the disease incidence in several localities in East and Northeast Russia and Yakutia-Sakha Republic indicated the restricted distribution of the rust in a few localities in Primorsky Territory. As previously reported in China,T. laricinum was proved to form uredinia in nature and to be able to propagate vegetatively by urediniospores. This suggests the fungus could become a devastating pathogen threatening a large-scale larch plantation in Far East of Russia. Field observations and the failure of basidiospore inoculation onto larch needles suggest the heteroecious life cycle ofT. laricinum.     

的吸附

以胶原纤维为基质,通过醛交联剂将杨梅单宁固化在胶原纤维上,制备固化杨梅单宁(IMT)吸附材料.研究该吸附材料对Pb2+、Cd2+ 和Hg2+的吸附性能.实验表明该吸附材料对这3种金属离子的吸附容量大小顺序为Hg2+>Pb2+ >Cd2+.吸附容量与pH值有关,pH值7时,对Hg2+的吸附容量最大;pH值3时,对Pb2+和Cd2+的吸附容量最大.在上述pH值条件下,当吸附剂用量为0.1 g,金属离子初始浓度为200 mg/L、体积为100 mL时,IMT对Hg2+、Pb2+、Cd2+的平衡吸附容量分别为198、87和24 mg/g.通过研究温度对吸附平衡的影响以及吸附动力学,发现IMT对Hg2+的吸附主要为化学吸附,对Pb2+的吸附可能包含物理吸附和化学吸附,对Cd2+的吸附以物理吸附为主,这与金属离子在水溶液中的状态有关.当水体中同时存在Hg2+和Pb2+时,IMT对每种金属离子的平衡吸附容量几乎不受其它金属离子的影响,即可以用于同时吸附除去这些金属离子.     

Effect of tree species on carbon stocks in forest floor and mineral soil and implications for soil carbon inventories

Forest soil organic carbon (SOC) and forest floor carbon (FFC) stocks are highly variable. The sampling effort required to assess SOC and FFC stocks is therefore large, resulting in limited sampling and poor estimates of the size, spatial distribution, and changes in SOC and FFC stocks in many countries. Forest SOC and FFC stocks are influenced by tree species. Therefore, quantification of the effect of tree species on carbon stocks combined with spatial information on tree species distribution could improve insight into the spatial distribution of forest carbon stocks.We present a study on the effect of tree species on FFC and SOC stock for a forest in the Netherlands and evaluate how this information could be used for inventory improvement. We assessed FFC and SOC stocks in stands of beech (Fagus sylvatica), Douglas fir (Pseudotsuga menziesii), Scots pine (Pinus sylvestris), oak (Quercus robur) and larch (Larix kaempferi).FFC and SOC stocks differed between a number of species. FFC stocks varied between 11.1 Mg C ha⁻¹ (beech) and 29.6 Mg C ha⁻¹ (larch). SOC stocks varied between 53.3 Mg C ha⁻¹ (beech) and 97.1 Mg C ha⁻¹ (larch). At managed locations, carbon stocks were lower than at unmanaged locations. The Dutch carbon inventory currently overestimates FFC stocks. Differences in carbon stocks between conifer and broadleaf forests were significant enough to consider them relevant for the Dutch system for carbon inventory.     

NaCl胁迫下沙枣幼苗的离子代谢特性

[Objective]To further understand the ion metabolism characteristics of Elaeagnus angustifolia L. under NaCl stress.[Method]The seedlings of two E. angustifolia L. provenances, which were Alaer (salt tolerance provenance) and Yinchuan (salt sensitive provenance), were treated by three NaCl concentrations (0,150,300 mmol·L^-1) and sampled at the 7th day and the 30th day to measure the Na⁺ , K⁺, Ca²⁺, and Mg²⁺ contents, K⁺/Na⁺ ratio and selective absorption and transportation of K⁺ in tissues (roots, stems and leaves). [Result]The results showed that the Na⁺ content in the organizations of E. angustifolia L. sharply increased with the increase of NaCl concentration. With prolonging of stress time, the Na⁺ content increased in roots, and decreased in stems and leaves. After seedlings of the two provenances were treated with 150 mmol·L^-1 NaCl for 7 days, the Na⁺ content was 2.10 times and 2.23 times in leaves, respectively, compared with the control groups, and was 1.79 times and 1.57 times in root. Meanwhile, the difference between two provenances showed a expanding trend with the increase of NaCl concentration and stress time. With the increase of NaCl concentration and extension of stress time, the K⁺ content, Ca²⁺ content and K⁺/Na⁺ ratio in organizations decreased gradually. Meanwhile, the Alaer provenance seedlings accumulated more Na⁺ in roots and less Na⁺ in leaves than that of Yinchuan provenance, and the K⁺ content, Ca²⁺ content and K⁺/Na⁺ ratio decreased less in the Alaer provenance seedlings than those of Yinchuan provenance. With the increase of NaCl concentration, the Mg²⁺ content in leaf gradually decrease, but the Mg²⁺ content in root increased 22.8~64.4% after salt stress for 7 days, and Alaer provenance seedlings increased more than Yinchuan provenance. After 30 days, there was non-significant difference with the control group on the Mg²⁺ content of root. K⁺ selective absorption of E. angustifolia L. seedlings significantly increased with increasing salt concentration of the media at the 7th days, whereas not obvious at the 30th days. When the concentration of NaCl in the media increased, the change of K⁺ selective transportation was not significant. [Conclusion]E. angustifolia L. seedlings increase Mg²⁺ content and K⁺ selective absorption in the roots at the early stage of salt stress to adapt saline environment. The salt-tolerance E. angustifolia L. provenance can cut off more Na⁺ in roots and reduce Na⁺ content in leaves, which cause less K⁺, Ca²⁺ and Mg²⁺ contents loss, especially the roots and leaves, so as to ensure that all kinds of metabolisms can go well.     

Relationships between larch growth and forest site factors

Dahurian larch (Larix gmelinii Rupr.) Rupr is one of the dominant species in both natural and man-made forests in northeast China. Effects of site factors, including topography, soil properties and nutrient elements (P, Ca, K, Mg, Mn, Zn, Cu, Ag, Co and Ni) on the growth of larch were analyzed in detail, qualitatively and quantitatively. The ordination technique was used to group the site factors and to classify sites for larch. Analysis indicated that height growth, diameter (DBH) and volume of the larch varied among site types and this will be of theoretical and practical significance in developing larch plantations.     

胶原纤维固化杨梅单宁对Mo(Ⅵ)的吸附

研究了胶原纤维固化杨梅单宁(IBT)这一新型吸附材料对Mo6 的吸附特性.实验表明,温度对吸附容量影响不大,而pH值对吸附容量有显著影响,Mo6 的吸附容量随pH值降低而增加,表明其吸附机理是吸附剂与聚钼阴离子之间的静电结合.当Mo6 的初始质量浓度为100.0mg/L、吸附剂用量0.100 g、温度为303 K、pH值2.0时,IBT对Mo6 的吸附量为82.4 mg/g.Freundlich方程可以很好地描述IBT对Mo6 的吸附等温线.动力学研究表明,初始吸附速率很快,吸附达到平衡的时间约为600 min,其吸附动力学可很好地用拟二级速率方程描述,计算所得的平衡吸附量与实测值误差很小.解吸实验表明,0.02 mol/L EDTA溶液能使吸附剂再生,并能循环使用.选择性吸附研究表明,在酸性(pH值2.0)条件下,IBT对Mo6 的吸附率大于95%,而对Ni2 和Cu2 的吸附率低于5%,可用于Mo6 -Ni2 和Mo6 -Cu2 二元混合溶液中Mo6 的分离和提取.     

Differences in spectral trajectory with stand volume development between Japanese larch and Japanese oak in Hokkaido,Japan

Our objective was to investigate the differences in the spectral trajectory of the LANDSAT Thematic Mapper with stand volume development between Japanese larch (Larix kaempferi) and Japanese oak (Quercus mongolica var. crispula) in the experimental forest of Kyushu University, Hokkaido, Japan. We used nonlinear regression and a categorical variable to investigate the relationship between spectral reflectance factor and stand volume for each forest type. This research showed that the reflectance factor of Japanese larch and Japanese oak reached saturation and that both forest types had different spectral trajectories with stand development. In addition, we found that middle of development stage (stand volume was between 100 and 200 m³/ha) of each forest type had similarity in reflectance factor.