Dispersion Mechanism Of Additives In High-concentration Organic Wastewater Slurry And Dispersion Control Mechanism

As our country pays more and more attention to the ecological environment,investment in wastewater treatment and water resources protection is also increasing.High-concentration organic wastewater contains a lot of organic matter and has some calorific value.If it can be used as a resource and reused effectively,it can turn waste into treasure at the same time of environmental treatment.Using high-concentration organic wastewater to synergistically prepare coal water slurry is an efficient way to utilize high concentration organic wastewater.This paper focuses on the dispersion control mechanism and additive action mechanism of high concentration organic wastewater coal slurry system by means of experiment and theoretical simulation,to provide theoretical basis and technical support for the practical engineering application of wastewater coal slurry.This article divides high-concentration organic wastewater into two categories:industrial organic wastewater with high moisture content and organic wastewater with strong hydrophobicity and low water content.Among them,organic wastewater with strong hydrophobicity is divided into oil-containing waste liquid and organic solvent.According to the different characteristics of these waste liquids,targeted research was carried out,and the additive adaptability experiment was carried out,combined with the coal-water interface characteristic experiment,to obtain the dispersion and stabilization mechanism of additives in different systems.The research results show that the effect of anionic additives in the industrial organic wastewater coal slurry is better,the effect of non-ionic additives in the oily wastewater coal slurry is better,and the effect of macromolecular additives in organic solvents is better.For the important components of wastewater,ammonia nitrogen and ester organic small molecules,this paper uses a combination of molecular dynamics simulation and adsorption experiments to study its effect on the adsorption of additives on the surface of coal particles and obtains microscopic characteristics such as adsorption configuration.The numerical simulation results of molecular density distribution and adsorption energy are obtained.The results show that in the ester organic small molecule solution,the adsorption amount of additives increases and the adsorption configuration is more compact,which is beneficial to increase the slurry concentration of coal water slurry.In the ammonia nitrogen solution,the adsorption amount of additives also increases,but double-layer adsorption occurs,which leads to an increase in the number of sealed water molecules in the hydration film and a decrease in free water in the solution,which is not conducive to increasing the slurry concentration.The extended DLVO theory is used to explain the dispersion and stability performance of the slurry system,considering the polar interaction energy,electrostatic interaction energy,van der Waals interaction energy and steric stabilization energy.Combining experimental measurement data such as contact angle,Zeta potential,ion concentration,and adsorption layer thickness,various interaction energies in the wastewater coal slurry system can be directly calculated,which provides theoretical guidance for the dispersion control of the system.The study found that the van der Waals interaction energy and the polar interaction energy in the coal water slurry system are both less than 0,which belong to attraction,while the electrostatic interaction energy and steric stabilization energy are both greater than 0,which belong to the repulsive force.To make the entire system in a dispersed and stable state,the total interaction energy of the system should be greater than 0.Therefore,macromolecular additives often have better dispersion stability performance,but at the same time,due to their obvious viscosity-increasing effect,it is necessary to balance the two properties of viscosity and stability.