排序方式: 共有12条查询结果,搜索用时 406 毫秒
1.
Shunitz Tanaka Masayuki Kawai Yosuke Nakata Motoki Terashima Hideki Kuramitz Masami Fukushima 《毒物与环境化学》2013,95(4-6):95-102
The photo-Fenton reactions, which could yield hydroxyl radicals via the catalytic degradation of H2O2 by Fe(II), were focused as one of the abiotic degradation processes of bisphenol A (BPA) in surface waters. At pH 6, in the presence of H2O2 only, 32% of BPA was degraded after 120?min of irradiation. However, 97% of BPA was degraded in the presence of both H2O2 and Fe(II). Without light irradiation, no BPA degradation was observed even in the presence of Fe(II) and H2O2. These results show that photo-Fenton processes are effective in the natural attenuation of BPA in surface water. In addition, the presence of humic acids (HAs), which were of more aliphatic nature, resulted in enhancing BPA degradation via the photo-Fenton processes. Therefore, HAs can be one of the important factors in enhancing the degradation of BPA in surface water via the photo-Fenton processes. 相似文献
2.
To suppress the coagulation of humic acid (HA) in aqueous solutions, HA was modified with hydrophilic amines, such as glucosamine or taurine. These amines were attached to carboxyl groups in HA via amide bond formation. The degree of modification (R(m)) was estimated to be 21-38%. Infrared spectra of the modified HAs were also consistent with the presence of amide bonds. Acid-base titration showed that the average acid-dissociation constant (pK(app)) of the HA samples was increased by the modification. The Ca(2+) binding capacity of HA decreased with an increase in R(m) value. Critical pH or Ca(2+) concentration, at which HA coagulation occurs, was increased as the result of the modification. These critical points for taurine-HA were higher than those for glucosamine-HA. This is mainly due to electrostatic repulsion by sulfonate groups in taurine. These results indicate that the coagulation of HA is suppressed by modifying the molecules with glucosamine or taurine. 相似文献
3.
Minoru Yoshikawa Yuko Motoki Go Hibino Kazuhiko Takeuchi Keisuke Hanaki Shinichi Arai Toshihiko Masui Toshihiro Inoue 《Sustainability Science》2011,6(2):169-175
Here we propose a method to quantitatively assess and examine Global No Net Loss (GNNL) of forest biodiversity on a global
scale. The method produces a GNNL index of existing forest and enables future predictions of forest loss under different assumptions.
The method tests the feasibility of the GNNL index and enables discussion of policy for future global scale sustainable forest
management up to 2050. The GNNL index was estimated from an equation including forest areas per country per forest type (primary
forest, secondary forest and plantation forest), diversity of forest ecosystem, and species density. Estimates derived from
historical data revealed an approximate 7% reduction in GNNL index between 1990 and 2005. Predictions of the GNNL index until
2050 emphasize the importance of regenerating large portions of forests felled for agricultural land (or other uses) with
secondary forests. 相似文献
4.
5.
The distribution behavior of pyrene on humic acid (HA)-kaolin complexes, prepared by adsorbing HA on kaolin, was investigated by batch experiments. The distribution coefficient (Kd) of pyrene on the HA-kaolin complex increased with the fraction (f(oc)) of organic carbon adsorbed to the surface of the kaolin. This can be attributed to hydrophobic interactions between pyrene and the adsorbed HAs. The effects of adsorbed HAs were quantitatively evaluated by calculating the distribution coefficient (K(oc)) and affinity constant (K(oc)ads) for pyrene to the adsorbed HAs. A fluorescence quenching method was employed to determine the affinity constant (K(oc)aq) of pyrene to HAs dissolved in an aqueous solution. When the K(oc) values were compared with the K(oc)aq values, the K(oc) values were found to be 4 to 11 times larger than the K(oc)aq values. On the other hand, the K(oc)ads values were 4 to 9 times larger than the K(oc)aq values. These indicate that the affinity for pyrene is enhanced by the adsorption of HAs to kaolin. In addition, the K(oc) values increased with increasing average molecular weights of the HAs. These results demonstrate that HAs, when they are adsorbed to clay minerals, play an important role in the deposition of polycyclic aromatic hydrocarbons (PAHs) in a soil environment. 相似文献
6.
7.
José Antônio Baptista Neto Thomas Ferreira da Costa Campos Carala Danielle Perreira de Andrade Susanna Eleonora Sichel Estefan Monteiro da Fonseca Akihisa Motoki 《Environmental geochemistry and health》2014,36(6):1199-1203
This work reports on the widespread occurrence of tar balls on a pebble beach of Sueste Bay on Fernando de Noronha Island, a Brazilian national marine park and a preserve in the South Equatorial Atlantic. Environmental regulations preclude regular visitors to the Sueste Bay beach, and the bay is a pristine area without any possible or potential sources of petroleum in the coastal zone. In this work, these tar balls were observed for the first time as they occurred as envelopes around beach pebbles. They are black in color, very hard, have a shell and coral fragment armor, and range in average size from 2 to 6 cm. The shape of the majority of the tar balls is spherical, but some can also be flattened ellipsoids. The polycyclic aromatic hydrocarbon analyses of the collected samples revealed the characteristics of a strongly weathered material, where only the most persistent compounds were detected: chrysene, benzo(b,k)fluoranthene, dibenzo(a,h)antracene and benzo(a)pyrene. 相似文献
8.
Makoto Tamura Motoharu Onuki Makiko Sekiyama Keishiro Hara Michinori Uwasu Nobuyuki Tsuji Gakushi Ishimura Noriyuki Tanaka Akihisa Mori Takashi Mino 《Sustainability Science》2018,13(3):849-860
The challenge for sustainability educational programs lies in how to imbue students with the strong motivation necessary to move the world in a more sustainable direction. Five universities in Japan have mutually collaborated in the design and development of a unique curriculum and education system for sustainability science since 2008. Specifically, they have developed a common and remote lecture system called the “Frontier of sustainability science” (FSS). This paper discusses the concepts and challenges of FSS and how it was organized to teach students to actively learn how to work with people of various disciplines to realize interdisciplinarity. 相似文献
9.
10.
Solubilizing abilities of aggregates of humic acid (HA) to chlorinated benzenes (CBs) were investigated by means of the apparent water solubility enhancement. Both the water solubilities of 1,4-dichlorobenzene (DCB) and 1,2,4,5-tetrachlorobenzene (TeCB) linearly increased with increasing concentration of HA above the critical micelle concentration (CMC). Such solubilization behavior of CBs for HA was compatible with those for sodium dodecyl sulfate (SDS). These results indicate that the solubilization of CBs in the aqueous solution of HA above the CMC can be interpreted on the basis of the phase-separation model. Thus, the partition coefficients (K(mic)) of CBs between water and HA aggregate phases were calculated by assuming this model. The fact that the K(mic) value increased with increasing K(ow) of CBs supported the partition into the HA aggregate phase by hydrophobic interaction. The estimated K(mic) values of DCB were not dependent on the solution pH. Both K(mic) values of DCB and TeCB for the HA aggregate were found to be 4-5-fold lower than those of SDS. 相似文献