The reactions for the reduction of

The reactions for the reduction of hexavalent chromium to trivalent chromium in aqueous solution are known. In addition, there are varying methods in the prior art to attempt to treat and stabilize chromium ore waste, which typically include the use of biological or chemical reduction. Bioremediation processes facilitate the reduction of Cr(VI) to Cr(III) through the use of anaerobic bacteria, whereas chemical reduction methods involve the addition of reducing agents and other reagents to the soil or material to be detoxified.
Many known processes designed for the reduction of Cr(VI) in soil and other waste materials are known as ex-situ methods, in which the soil must be excavated and fed through a reactor or apparatus for treatment. In a typical ex-situ process, such as that disclosed by U.S. Pat. No. 5,304,710, the soil, once excavated, is placed in a reactor and ground. The pH of the soil is then adjusted to an appropriate level and combined with a reduction agent, typically ferrous sulfate, to reduce the hexavalent chromium. Assuming that ferrous sulfate is used as the reducing agent, the following redox reaction applies: C r0 42-+3Fe2++4H20 —Cr3++3Fe3++ 8 0 t T F ollow ing reduction, fu rth er treatm ents, such as neutralization, may be performed on the soil. The drawbacks generally of ex-situ processing methods are that large reactors must be constructed and the soil to be treated must be excavated and transported to the reactor for treatment, processes which are not efficient on a large scale and can be very costly and hazardous with respect to the transfer of contaminated materials.
In-situ methods of soil detoxification are more practical, cost effective and safer, especially when large areas of land must be treated. In this type of approach, one or more reagents are added to the soil (e.g., in the field) to bring about the reduction. Clear advantages are the elimination of both the reactor and the need for excavation. One such method is disclosed by U.S. Pat. No. 5,951,457 and involves the addition of ascorbic acid to the soil to reduce the Cr(VI) to Cr(III). In order to ensure that the chromium in the soil below the ground level is reduced, the soil must be mechanically mixed with the ascorbic acid. Although this method is designed to treat soil significantly below the ground level, extremely large quantities of the acid are necessary. As a result, the process is not economically feasible on a large scale due to the high costs of purchasing and transporting large quantities of ascorbic acid.
Other methods have been proposed for the addition of chemical reducing agents to the soil. These include (1) first drilling holes in the ground prior to introducing the reagent; and (2) utilizing a rototiller or similar device to thoroughly mix the soil with the reducing agent. One such method, directed toward the reduction of Cr(VI), is described in U.S. Pat. No. 5,285,000. However, delivery methods designed to inject solutions into soil are typically not effective methods of delivery because they do not typically provide even distribution of the reagent to the targeted contaminants. Additionally, the process involves dissolving and mixing ferrous and ferric salts in large quantities of water to produce the reducing solutions, which is likely to be quite costly.
A further such method in U.S. Pat. No. 5,397,478 is directed to the in-situ reduction of Cr(VI) in soil. This patent demonstrates the use of hole-drilling only on a very small test plot of soil in a laboratory. It does not provide guidance on how to feasibly implement such techniques practically on a large land area, in which the depth of the soil is significant, and/or in which large volumes of soil would be required to be mixed with or otherwise contacted with the reducing agents.

結果 (中文) 1:

已知的反应的六价铬还原为三价铬在水溶液中。此外，事先的艺术尝试处理和稳定铬矿石废物，其中通常包括生物或化学减少使用有不同的方法。生物修复过程促进六价铬对家兔利用厌氧细菌，减少反之化学还原方法包括加入还原剂和其他试剂对土壤或材料要彻底戒除毒瘾。土壤中的六价铬还原为设计的许多已知的进程和其他废物的材料被称为迁地方法，必须挖掘和美联储通过反应堆或治疗仪土壤。在典型的迁地过程中，如由美国 Pat 披露。号 5,304,710，土壤，一次出土，被摆在反应器和地面。土壤的 ph 值是调整到一个适当的水平，然后结合还原剂，通常硫酸亚铁，以减少六价铬。假设硫酸亚铁用作还原剂，适用以下的氧化还原反应: C r0 42-+ 3Fe2 + + 4 H 20 — — Cr3 + + 3Fe3 + + 8 0 t T F 跟 ing 减少，福 rth 呃处理经济需求测试，如失效，可能执行的土壤。缺点一般的就地加工方法，是必须建造大型反应堆和必须挖掘和输送到反应器处理土壤受到善待，处理，并不是很大程度上有效，可以非常昂贵和危险转让受污染的材料。原位土壤解毒方式更实用、 成本有效和安全，特别是当必须治疗大面积的土地。在这种类型的方法，一个或多个试剂被添加到 (例如，在字段) 土壤带来的减少。明显的优势是电抗器和开挖需要消除。由美国 Pat 公开了一种方法。号 5,951,457，是加入到土壤，以减少对家兔六价铬抗坏血酸。为了确保低于地面土壤中的铬减少，必须与抗坏血酸机械混合土。虽然此方法为了治疗显著低于地面土壤，极其大量的酸是必要的。因此，过程不是抗坏血酸的大规模的采购和运输大量高成本经济上可行的。添加化学还原剂对土壤提出了其他方法。这些包括 (1) 第一孔在地面之前引入试剂;和 (2) 利用旋耕机或类似的设备，彻底混合土壤与还原剂。美国帕特描述了这样一种方法，针对六价铬，减少。号 5,285,000。然而，交付方法设计解决方案注入土壤通常不是试剂的交付的有效方法，因为他们通常并不提供均匀分布的污染物，有针对性。此外，这个过程包括溶解和混合铁和铁盐在大量的水产生减少的解决方案，这是可能要付出很大代价。另外这种方法在美国八个。号 5,397,478 被针对在原位还原六价铬的土壤中。这项专利演示孔钻只在很小的试验田土壤的实验室的使用。它不能如何切实在土地面积大，在深度的土壤具有重大意义，并且/或者在其中大量的土壤将须与混合或否则联系与还原剂切实执行这类技术指导。

結果 (中文) 3:

对六价铬的还原水溶液中三价铬的反应是已知的。此外，在现有技术中，有不同的方法来处理和稳定的铬矿石废物，通常包括使用生物或化学还原。生物修复过程有利于利用厌氧菌对铬（Ⅲ）的还原反应，而化学还原方法包括还原剂和其他试剂添加到土壤或材料被解毒。
许多已知的过程设计为还原Cr（VI）在土壤和其他废弃物被称为迁地保护的方法，其中土壤必须开挖和送入反应器或处理设备。在典型的易地过程，如美国拍拍披露。5304710号，土壤，一旦挖掘出来，被放置在一个反应器和地面。然后是土壤的pH值调整到合适的水平，并结合典型的还原剂，硫酸亚铁，减少六价铬。假设使用硫酸亚铁作为还原剂，下列氧化还原反应适用：C R0 42 3fe2 4h20 -铬3fe3 8 0 T T跟ING还原，傅RTH二治疗老年，如中和，可以对土壤进行。一般的易地处理方法的缺点是，大的反应器必须被构造和被处理的土壤必须被挖掘和运送到反应器处理，在大尺度上没有效率的过程，对污染物质的转移可能是非常昂贵和危险的，而土壤解毒的原位方法更实用，更安全，更安全，特别是在大面积的土地必须处理。在这种类型的方法中，一个或多个试剂被添加到土壤中（例如，在外地）带来的减少。清除的优点是消除反应器和需要进行挖掘。美国拍拍透露了这样一种方法。5951457号和加入的抗坏血酸，以减少土壤中的铬（六），铬（Ⅲ）。为了保证土壤中的铬含量降低，土壤必须机械混合与抗坏血酸。虽然这种方法的目的是治疗土壤显着低于地面的水平，非常大的量的酸是必要的。其结果是，在一个大的规模，由于采购和运输大量的抗坏血酸的高成本的过程是经济上不可行的。其他方法已被提出的化学还原剂的土壤中加入。这些包括：（1）首先钻进地洞引入剂之前；和（2）利用旋耕机或类似装置彻底混合土壤的还原剂。一个这样的方法，针对减少铬（六），在美国的拍拍。5285000号。不过交付的方法设计为土壤中的解决方案通常是不有效的方法，因为他们通常不会提供的试剂，即使分配到目标污染物。此外，该过程包括溶解和混合铁和三价铁的盐在大量的水，以产生减少的解决方案，这是可能是相当昂贵的。