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更新時間：2024-11-14 09:26:28
有效期：2024年11月14日 -- 2025年5月17日
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北京百奧創(chuàng)新代理International Humic在中國的業(yè)務。International Humic代理，International Humic 代理，International Humic華東代理，International Humic華北代理，International Humic華中代理，International Humic華南代理，International Humic 代理
Humic substances (HS) are complex and heterogeneous mixtures of polydispersed materials formed in soils, sediments, and natural waters by biochemical and chemical reactions during the decay and transformation of plant and microbial remains (a process called humification). Plant lignin and its transformation products, polysaccharides, melanin, cutin, proteins, lipids, nucleic acids, fine char particles, etc., are important components taking part in this process. Humic substances are involved in many processes in soils and natural waters: e.g., soil weathering, plant nutrition, pH buffering, trace metal mobility and toxicity, bioavailability, degradation and transport of hydrophobic organic chemicals, formation of disinfection by-products during water treatment, and heterotrophic production in blackwater ecosystems. Accordingly, humic substances have received attention from scientists in a wide variety of disciplines.International Humic 代理
International Humic 代理，International Humic產(chǎn)品列表：
| Cat. No. | Source | Carboxyl | Phenolic | Q1 | Log K1 | n1 | Q2 | Log K2 | n2 | N | RMSE | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
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| Sources: (1) School of Earth & Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, U.S.A.; (2) Department of Chemistry, Environmental Sciences Ph.D. Program, Ball State University, Muncie, IN, U.S.A. | ||||||||||||
| References: (1) J. D. Ritchie and E. M. Perdue, Geochim. Cosmochim. Acta, 67, 85-96 (2003); (2) S. J. Driver and E. M. Perdue, Advances in the Physicochemical Characterization of Dissolved Organic Matter: Impact on Natural and Engineered Systems, American Chemical Society, 1160: 75-86 (2014). | ||||||||||||
| Solutions containing 0.36 ± 0.01 g L-1 (on a dry ash-free basis) of an IHSS sample in 0.1 M NaCl were titrated from their initial pH values of 3.0-3.3 to final pH values of 10.5-10.7 in 25-35 minutes, using 6-8 mL increments of carbonate-free 0.100 M NaOH. All titrations were conducted under a N2 atmosphere in a thermostated water bath at 25.00 ± 0.02 °C. At least three titrations were obtained for each sample. The stock solutions of soil, peat, leonardite, and Summit Hill humic acids also contained 0.002 M NaOH, which was needed to effectively disperse/dissolve those samples, and an equivalent quantity of HCl that was added just before a titration was started. | ||||||||||||
| Carboxyl is the charge density (meq/g C) at pH 8.0; Phenolic is two times the change in charge density (meq/g C) between pH 8.0 and pH 10.0. | ||||||||||||
| The overall charge density (in meq/g C) of a humic substance increases systematically with pH (or with the concentration of H+). The equation on the right, known historically as a modified Henderson-Hasselbalch equation for two classes of binding sites, was used to fit titration data and obtain the set of model fitting parameters in this table. |  | |||||||||||
| The fitting parameters of the model were obtained by a nonlinear least-squares fit of the model to aggregated sets of replicate titration data. Q1 and Q2 are the maximum charge densities of the two classes of binding sites, Log K1 and Log K2are the mean log K values for proton binding by the two classes of sites, and n1 and n2 are empirical parameters that control the width (in log K) of a class of proton binding sites. N is the number of fitted titration data points, and RMSE is the root mean-square error for fitting this model to the data (see Reference). This model, also known in more recent literature as a Langmuir-Freundlich equation, is the primary building block of the NICA class of models. | ||||||||||||
| An * means that a sample is no longer available, and nd means that an item was not determined. | ||||||||||||
| Standard HA | ||||||||||||
| Suwannee River I * | 1S101H | (1) | 9.59 | 4.24 | 10.69 | 4.42 | 3.79 | 2.28 | 9.68 | 1.11 | 113 | 0.0673 |
| Suwannee River II | 2S101H | (1) | 9.13 | 3.72 | 9.74 | 4.35 | 3.30 | 4.48 | 10.44 | 1.73 | 171 | 0.0815 |
| Elliott Soil | 1S102H | (1) | 8.28 | 1.87 | 8.90 | 4.36 | 3.16 | 0.85 | 9.80 | 1.00 | 169 | 0.0943 |
| Pahokee Peat | 1S103H | (1) | 9.01 | 1.91 | 9.64 | 4.22 | 3.20 | 0.94 | 9.86 | 1.00 | 145 | 0.0865 |
| Leonardite | 1S104H | (1) | 7.46 | 2.31 | 8.17 | 4.59 | 3.32 | 1.13 | 9.72 | 1.31 | 106 | 0.0532 |
| Standard FA | ||||||||||||
| Suwannee River I | 1S101F | (1) | 11.44 | 2.91 | 12.00 | 3.80 | 3.21 | 1.48 | 9.52 | 1.00 | 109 | 0.1053 |
| Suwannee River II | 2S101F | (1) | 11.17 | 2.84 | 11.66 | 3.76 | 3.24 | 2.05 | 9.84 | 1.45 | 123 | 0.1072 |
| Elliott Soil I * | 1S102F | (1) | nd | nd | nd | nd | nd | nd | nd | nd | nd | nd |
| Elliott Soil II | 2S102F | (1) | 13.24 | 2.27 | 14.12 | 3.67 | 3.62 | 0.74 | 9.53 | 1.00 | 111 | 0.1375 |
| Pahokee Peat I * | 1S103F | (1) | 13.34 | 2.32 | 14.22 | 3.99 | 3.33 | 0.76 | 9.57 | 1.00 | 117 | 0.1028 |
| Pahokee Peat II | 2S103F | (1) | nd | nd | nd | nd | nd | nd | nd | nd | nd | nd |
| Reference HA | ||||||||||||
| Suwannee River * | 1R101H | (1) | nd | nd | nd | nd | nd | nd | nd | nd | nd | nd |
| Pahokee Peat | 1R103H | (1) | 8.87 | 2.05 | 9.54 | 4.26 | 3.25 | 1.01 | 9.85 | 1.00 | 117 | 0.0773 |
| Nordic Lake | 1R105H | (1) | 9.06 | 3.23 | 10.32 | 4.32 | 4.22 | 1.64 | 9.89 | 1.11 | 105 | 0.0740 |
| Summit Hill Soil | 1R106H | (1) | 7.14 | 2.42 | 7.53 | 4.47 | 3.12 | 1.31 | 9.23 | 1.57 | 106 | 0.0480 |
| Waskish Peat | 1R107H | (1) | nd | nd | nd | nd | nd | nd | nd | nd | nd | nd |
| Reference FA | ||||||||||||
| Suwannee River | 1R101F | (1) | 12.23 | 3.11 | 12.94 | 3.81 | 3.36 | 1.60 | 9.62 | 1.00 | 115 | 0.1312 |
| Pahokee Peat * | 1R103F | (1) | 15.24 | 1.78 | 16.25 | 3.73 | 3.54 | 1.31 | 10.74 | 1.00 | 129 | 0.1586 |
| Nordic Lake | 1R105F | (1) | 11.16 | 3.18 | 12.15 | 3.79 | 3.95 | 1.49 | 9.67 | 1.00 | 107 | 0.1121 |
| Waskish Peat | 1R107F | (1) | nd | nd | nd | nd | nd | nd | nd | nd | nd | nd |
| Pony Lake FA | 1R109F | (2) | 7.09 | 1.75 | 6.91 | 4.52 | 1.92 | 1.43 | 9.48 | 1.77 | 1256 | 0.0340 |
| Aquatic NOM | ||||||||||||
| Suwannee River I | 1R101N | (1) | 9.85 | 3.94 | 10.57 | 3.94 | 3.60 | 2.61 | 9.74 | 1.19 | 112 | 0.0725 |
| Suwannee River II | 2R101N | (2) | 11.21 | 2.47 | 11.20 | 4.16 | 3.44 | 1.60 | 9.99 | 1.03 | 1705 | 0.1360 |
| Nordic Lake | 1R108N | (1) | nd | nd | nd | nd | nd | nd | nd | nd | nd | nd |
| Upper Mississippi River | 1R110N | (2) | 12.43 | 0.83 | 12.51 | 3.47 | 2.69 | 0.91 | 10.00 | 1.00 | 1626 | 0.0800 |
| Bulk Materials | ||||||||||||
| Elliott Soil | BS102M | (1) | nd | nd | nd | nd | nd | nd | nd | nd | nd | nd |
| Pahokee Peat | BS103P | (1) | nd | nd | nd | nd | nd | nd | nd | nd | nd | nd |
| Leonardite | BS104L | (1) | nd | nd | nd | nd | nd | nd | nd | nd | nd | nd |
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