Sediment Adsorption Measurement Device with Peristaltic Circulation
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Solution Overview
Problem
Current methods for measuring the adsorption/desorption characteristics of surface bed sediments fail to accurately simulate the interaction between sediments and pore water, and the permeable boundary conditions, leading to overestimation of contaminant adsorption and inability to quantify adsorption/desorption in thin-layer sediments.
Innovation Solution
A device comprising a reaction cylinder, liquid collection cylinder, and liquid circulating member with vent holes and a peristaltic pump, allowing for controlled permeation pressure and full exchange between overlying water and pore water, enabling experiments on sediments of any thickness, including thin layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If batch experiment with orbital shaker incubator is used, then adsorption/desorption capability of sediment particles can be researched, but adsorption characteristic of bed sediments in natural arrangement mode cannot be derived and water-sediment contact area is greatly increased leading to over-estimation
Solution Approach 1:
The device segments the sediment body into multiple thin layers (each layer thickness can be controlled, e.g., 1-5 cm) stacked vertically in the reaction cylinder. This segmentation maintains the natural layered arrangement of bed sediments while allowing controlled water-sediment contact at each interface, preventing over-estimation of adsorption capacity that occurs in batch experiments where all sediments are fully mixed and contacted.
Solution Approach 2:
The invention transitions from the horizontal mixing approach of batch experiments to a vertical column configuration where water flows downward through stacked sediment layers. This dimensional change from horizontal to vertical arrangement preserves the natural stratification of bed sediments and creates realistic water-sediment interaction conditions, allowing accurate measurement of adsorption characteristics in the arrangement mode of bed sediments.
2Reliability
If conventional soil column experiment is used, then permeability of pore water in soil layers can be considered, but adsorption/desorption capability of certain soil layers cannot be quantitatively measured and permeation pressure cannot be controlled
Solution Approach 1:
The device applies local quality by equipping each sediment layer with individual sampling ports and flow measurement devices. This allows separate quantification of adsorption/desorption capacity for each layer (e.g., surface layer vs. deeper layers) while maintaining controlled permeation pressure through the entire column. The local measurement capability enables precise determination of adsorption characteristics for specific soil layers rather than averaging across the entire column.
Solution Approach 2:
The invention introduces dynamic control of permeation pressure through a pressure control system that can adjust and maintain specific pressure values during experiments. This dynamic pressure control allows simulation of different natural conditions (e.g., varying water levels, flow rates) and enables quantitative measurement of adsorption/desorption under controlled permeation pressures, overcoming the static natural permeation limitation of conventional soil columns.
3Measurement precision
If batch experiment with orbital shaking method is used, then isothermal adsorption curve and adsorption kinetic curve can be obtained, but characteristics of interaction between bed sediments and pore water cannot be derived
Solution Approach 1:
The invention introduces pore water as an intermediary medium between the overlying water and the sediment layers. The pore water circulates through the sediment pores, mediating the interaction between contaminants and sediments. This intermediary system allows derivation of water-sediment interaction characteristics by measuring contaminant concentrations in pore water at different depths and times, providing insights into the mechanisms of adsorption/desorption that cannot be obtained from batch experiments where direct water-sediment contact occurs without pore water mediation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device provides accurate adsorption/desorption kinetic and isothermal curves, quantifying adsorption capacity per unit mass or area, and simulates natural conditions, offering more realistic data for water ecological models and improving environmental assessments.
Implementation Method 1
a liquid circulating member consisting of rubber pipes and a peristaltic pump; one end of the rubber pipes is connected to the bottom of the liquid collection cylinder, and the other end is connected to the side wall of the reaction cylinder
Implementation Method 2
The contaminants in the overlying water are mainly absorbed/desorbed by bed sediment through ion diffusion and exchange of overlying water with pore water
Implementation Method 3
The contaminants in the overlying water are mainly absorbed/desorbed by bed sediment through ion diffusion and exchange of overlying water with pore water
Implementation Method 4
Bed sediment mainly adsorb contaminants through interaction with pore water
Implementation Method 5
The contaminants in the overlying water are mainly absorbed/desorbed by bed sediment through ion diffusion and exchange of overlying water with pore water
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
The present invention discloses a device for measuring adsorption/desorption of contaminants onto surface bed sediments and a method of using the device. The measurement device includes a sediment sample disc, a sample holder, a reaction cylinder, a liquid collection cylinder, and a liquid circulating member from inside to outside, the liquid circulating member consisting of rubber pipes and a peristaltic pump. According to the method of using the device for measuring the adsorption/desorption of contaminants onto surface bed sediments, the full contact of bed sediments with pore water and the full exchange of overlying water with pore water are realized through liquid circulation without changing the arrangement modes of the bed sediments; any thickness of bed sediments can be performed on experiments, particularly for thin-layer bed sediments; and natural permeation and accelerated permeation of pore water through bed sediments can be switched simply by adjusting the flow rates of the peristaltic pump and by opening/closing of vent holes. Adsorption characteristic parameters obtained through the device and the method provide, for water quality models, data support which conforms to the natural existing condition of bed sediments and is more scientific and reasonable, and the device and the method achieve significant environmental benefits.