What affects the accuracy and applicability of determining wastewater sludge water content via low-field nuclear magnetic resonance?
What affects the accuracy and applicability of determining wastewater sludge water content via low-field nuclear magnetic resonance?
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DOI：
10.1016/j.envres.2023.115702
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发表时间：
2023-03
影响因子：
8.3
通讯作者：
Ya-Li Zhang;Ping-He Sun;Bing-Bing Dai-Bing;Shao-Ming Zheng;Dan Ran;Tian-Xin Wu;R. Zeng;Hou-Feng Wang
中科院分区：
文献类型：
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作者：
Ya-Li Zhang;Ping-He Sun;Bing-Bing Dai-Bing;Shao-Ming Zheng;Dan Ran;Tian-Xin Wu;R. Zeng;Hou-Feng Wang
废弃污泥含水量的准确测定对于污泥脱水处理及其处置管理至关重要。尽管之前的研究强调了低场核磁共振（LF-NMR）在测定污泥含水量方面的巨大优势，但其准确性和适用性尚未得到很好的研究。在此，本研究研究了操作参数的确定和污泥样品的性质对低频核磁共振方法测量污泥含水量的准确性和适用性的影响。结果表明，标准曲线、扫描次数（NS）、样品重量等基本参数的设置影响LF-NMR污泥含水量的准确度。以3 g/L CuSO4、NS = 8、样品重量约5 g构建的标准校准曲线适合污泥含水量的准确测定。此外，污泥中磁性物质的存在会影响主磁场的分布梯度，从而限制了LF-NMR的适用性。化学试剂的饱和磁化强度与污泥含水量测量的相对误差强相关（r=0.995，p<0.01），磁性材料的饱和磁化强度越大，测试结果的误差越大。总体而言，评价LF-NMR方法的准确性和适用性需要充分考虑工艺参数和污泥性质的影响，而不是简单照搬文献中的参数。
The accurate determination of waster sludge water content is crucial to sludge dewatering treatment and its disposal management. Though previous studies highlight the great advantages of low-field nuclear magnetic resonance (LF-NMR) in the determination of sludge water content, its accuracy and applicability are not well studied. Herein, this study investigated the settling of operating parameters and the properties of sludge samples on the accuracy and applicability of LF-NMR method in measuring sludge water content. The results showed that the setting of basic parameters such as standard curve, number of scanning times (NS) and sample weight affected the accuracy of sludge water content by LF-NMR. The standard calibration curve constructed by 3 g/L CuSO4, NS = 8 and the sample weight of about 5 g, were suitable for the accurate determination of sludge water content. Furthermore, the existence of magnetic substances in sludge can affect the distribution gradient of main magnetic field, and thus restricted the applicability of LF-NMR. The saturation magnetization of chemical reagents strongly correlated with the measured relative errors of sludge water content (r = 0.995, p < 0.01), the greater the saturation magnetization of the magnetic material, the greater the error of the test results. On the whole, it is necessary to fully consider the influence of process parameters and sludge properties to evaluate the accuracy and applicability of the LF-NMR method, rather than simply copying the parameters in literatures.