水质 悬浮物的测定 重量法
Water quality－Determination of suspended substance
－Gravimetric method
GB 11901-89
1 主题内容和适用范围
本标准规定了水中悬浮物的测定。
本标准适用于地面水、地下水，也适用于生活污水和工业废水中悬浮物测定。
2 定义
水质中的悬浮物是指水样通过孔径为0.45μm的滤膜，截留在滤膜上并于103～105℃烘干至恒重的物质。
3 试剂
蒸馏水或同等纯度的水。
4 仪器
4.1 常用实验室仪器和以下仪器。
4.2 全玻璃微孔滤膜过滤器。
4.3 GN－CA滤膜、孔径0.45μm、直径60mm。
4.4 吸滤瓶、真空泵
4.5 无齿扁咀镊子。
5 采样及样品贮存
5.1 采样
所用聚乙烯瓶或硬质玻璃瓶要用洗涤剂洗净。再依次用自来水和蒸馏水冲洗干净。在采样之前，再用即将采集的水样清洗三次。然后，采集具有代表性的水样500～1 000mL,盖严
瓶塞。
注：漂浮或浸没的不均匀固体物质不属于悬浮物质，应从水样中除去。
5.2 样品贮存
采集的水样应尽快分析测定。如需放置，应贮存在4℃冷藏箱中，但最长不得超过七天。
注：不能加入任何保护剂，以防破坏物质在固、液间的分配平衡。
6 步骤
6.1 滤膜准备
用扁咀无齿镊子夹取微孔滤膜放于事先恒重的称量瓶里，移入烘箱中于103～105℃烘干半小时后取出置干燥器内冷却至室温，称其重量。反复烘干、冷却、称量，直至两次称量的重量差≤0.2mg。将恒重的微孔滤膜正确的放在滤膜过滤器(4.1)的滤膜托盘上，加盖配套的漏斗，并用夹子固定好。以蒸馏水湿润滤膜，并不断吸滤。
6.2 测定
量取充分混合均匀的试样100mL抽吸过滤。使水分全部通过滤膜。再以每次10mL蒸馏水连续洗涤三次，继续吸滤以除去痕量水分。停止吸滤后，仔细取出载有悬浮物的滤膜放在原恒重的称量瓶里，移入烘箱中于103～105℃下烘干一小时后移入干燥器中，使冷却到室温，称其重量。反复烘干、冷却、称量，直至两次称量的重量差≤0.4mg为止。
注：滤膜上截留过多的悬浮物可能夹带过多的水份，除延长干燥时间外，还可能造成过滤困难，遇此情况，可酌情少取试样。滤膜上悬浮物过少，则会增大称量误差，影响测定精度，必要时，可增大试样体积。一般以5～100mg悬浮物量做为量取试样体积的实用范围。
7 结果的表示
悬浮物含量C(mg/L)按下式计算：
式中：C——水中悬浮物浓度，mg/L；
A——悬浮物＋滤膜＋称量瓶重量，g；
B——滤膜＋称量瓶重量，g；
V——试样体积，mL。
附加说明：
本标准由国家环保局标准处技术提出。
本标准由烟台市环境监测中心站负责起草。
本标准主要起草人李长海、王文法。
本标准委托中国环境监测总站负责解释。
Water quality－Determination of suspended substance
－Gravimetric method
GB 11901-89
1. Applicable scope
It is ud to test the SS in Water
It can be ud for testing the SS in the surface or underground water, also can be ud to test domestic water and industrial waste water.
2 Definition
The suspended substance is the stuff which is left on the filter film after being filtered with the hole diameter of um0.45 and has been dried in 103 to 105℃ condition to standing weight.
3 Reagent
Distilled water or the water with same purity
4 Apparatus
4.1 Normal lab apparatus plus below ones
4.2 Glass type micro film filter
4.3 GN-CA filter film, hole diameter 0.45um, Diameter 60mm.
4.4 Suction bottle, vacuum pump
4.5 Flat type tweezer
5 Sampling and sample storage
5.1 Sampling
The polyethylene bottle or hard glass bottle should be cleaned with detergent and then washed by tap water and distilled water respectively. Before sampling, it should be cleaned with the sample water 3 times. Then reprentative water sample should be taken at the volume of 500 to 1000ml, cover the cap tightly.
Note: The non-consistent solid material floating or submerged can not be regarded as SS, which should be removed from the water sample.
5.2 Sample storage
The water sample should be analyzed ASAP. If it needs to be stored for some time, it should be stored in the refrigerator at 4 ℃. But the duration can not be longer than 7 days.
Note: It is not allowed to add any protection agent to avoid the damage on the balance of solid and liquid pha.
6. Procedure
6.1 Filtering film preparation
Firstly, take the microporous film and put it on the standing weight bottle. Then it will be dried in the oven for half an hour at the temperature of 103 to 105℃. After that, it will be moved out to cool in the dryer until its temperature drops to room temperature. It should be dried, cooled and weighted repeatedly until the weight difference between two subquent weighing is less than 0.2mg. Then the microporous film at constant weight sh
ould be correctly put on the film support tray and matching hopper should be equipped. Then it should be fastened with clamp. Wet the film with the distilled water and filtration and suction should be continuous.
6.2 Test
It is to suck 100ml of homogeneously mixed sample for filtering to get the water running through the microporous film. Next , wash it 3 times concutively with 10ml of distilled water each time. Continue suction and filtration until getting the residual water away. After stopping filtering, put the film with SS left on top in the weighing bottle and then put them in the oven with the temperature of 103 to 105℃ for 1 hr. Then take it to the dryer to cool down to room temperature. Following step is to weigh it. The drying, cooling, and weighing should be repeated until the weight difference of two concutive weightings is less than 0.4mg.
Note: Excessive SS on the top of microporous film may contain surplus moisture, which will increa the difficulty of filtering besides longer drying time. In that ca, we can redu
ce the sampling volume slightly. On another hand, less SS on the film will also rai the weighing error and affect the measurement precision. thus, sampling volume should be incread correspondingly. Normally the sampling is done in the sample ranging from 5 to 100mg of SS.
