阅读说明：本技术 一种基于能耗（ee/o）计算紫外高级氧化工艺氧化剂最佳投加浓度的方法 (Method for calculating optimal adding concentration of oxidant in ultraviolet advanced oxidation process based on energy consumption (EE/O) ) 是由 孙佩哲 孟坛 罗芮桓 于 2021-09-07 设计创作，主要内容包括：本发明属于环境工程水处理领域,具体涉及一种基于能耗(EE/O)计算紫外高级氧化工艺氧化剂最佳投加浓度的方法。主要包括：两个用于计算紫外高级氧化工艺氧化剂最佳投加浓度(基于能耗)的简单公式。本发明为工程应用中基于紫外的高级氧化工艺氧化剂投加浓度的优化提供一种简单的计算方法,并为基于紫外的高级氧化工艺在工程上的推广应用提供理论指导。(The invention belongs to the field of water treatment in environmental engineering, and particularly relates to a method for calculating the optimal adding concentration of an oxidant in an ultraviolet advanced oxidation process based on energy consumption (EE/O). The method mainly comprises the following steps: two simple formulas for calculating the optimal adding concentration (based on energy consumption) of the oxidant in the ultraviolet advanced oxidation process. The invention provides a simple calculation method for optimizing the adding concentration of the oxidant in the ultraviolet-based advanced oxidation process in engineering application, and provides theoretical guidance for the popularization and application of the ultraviolet-based advanced oxidation process in engineering.)

1. A method for calculating the optimal adding concentration of an oxidant in an ultraviolet advanced oxidation process based on energy consumption (EE/O) mainly comprises the following steps: two formulas for calculating the optimal adding concentration of the oxidant in the ultraviolet advanced oxidation process are as follows:

1) first, UV/H with only OH as a single PRS₂O₂For example, a calculated UV/H is derived based on EE/O₂O₂(C) of optimum concentration of oxidant_opt-EE/O) The formula:

2) will be based on [. OH]_ssThe derived simple formula is popularized and applied to other UV generating various PRSs-based AOPs including UV/FAC, UV/PDS;

3) will be based on [. OH]_ssThe derived simple formula is transformed and then popularized and applied to UV/NH₂Cl

2. The two formulas for calculating the optimal adding concentration of the oxidant in the ultraviolet advanced oxidation process based on energy consumption according to claim 1 are characterized in that:

1) the formula obtained by derivation can quickly and accurately measure the optimal adding concentration of the oxidant of the ultraviolet advanced oxidation process based on energy consumption, and theoretical guidance is provided for the application of the ultraviolet advanced oxidation process in the aspect of water treatment;

2) the formula for calculating the optimal adding concentration of the oxidant in the ultraviolet advanced oxidation process based on energy consumption, which is obtained by derivation, can be popularized and applied to other ultraviolet-based advanced oxidation processes (such as UV/FAC, UV/PDS and UV/NH)₂Cl, etc.) to provide a simple evaluation method for the optimization of the energy consumption of the engineering;

3) the formula for calculating the optimal adding concentration of the oxidant in the ultraviolet advanced oxidation process based on energy consumption, which is obtained by derivation, provides a simple method for comparison of different ultraviolet advanced oxidation processes.

Technical Field

The invention belongs to the field of photocatalytic degradation of organic micropollutants, and particularly relates to a method for calculating the optimal adding concentration of an oxidant in an ultraviolet advanced oxidation process based on energy consumption (EE/O).

Background

The threats of organic micropollutants such as drug pollutants, odor substances, endocrine disruptors, disinfection byproducts, algal toxins and the like to the quality of drinking water are wide. These organic micropollutants not only have a serious impact on water ecology, but also are a serious health hazard to humans. Ultraviolet-based advanced oxidation processes (UV-based AOPs) have received much attention because they can effectively remove organic contaminants from water.

UV-based AOPsChemical oxidizing agents are often used, such as hydrogen peroxide (H)₂O₂) Free chlorine (FAC), Peroxodisulfate (PDS), monochloramine (NH)₂Cl), etc., which can effectively reduce pollutants in water by generating highly active radicals in combination with ultraviolet irradiation. Optimization of energy consumption is an important issue in the field of water treatment for ultraviolet-based advanced oxidation processes, wherein EE/O (kWh. L)^-1) The values are the most common evaluation indices for UV-based AOPs in engineering applications. In engineering applications, EE/O is typically optimized based on both oxidant dosing and electrical energy consumption to achieve treatment goals with minimal operating costs. However, due to the lack of theoretical research on process optimization, the engineering application of UV-based AOPs is generally optimized one by one according to the requirements of water plants, which limits the wide-range popularization and application of UV-based AOPs in engineering.

In view of the above, there is a need for a simple and efficient method for optimizing the oxidant dosing concentration of the uv advanced oxidation process in engineering applications based on energy consumption (EE/O).

Disclosure of Invention

The invention aims to provide a method for calculating the optimal adding concentration of an oxidant in an ultraviolet advanced oxidation process based on energy consumption (EE/O), a formula is obtained by deduction, a simple calculation method is provided for the optimization of the adding concentration of the oxidant in the ultraviolet-based advanced oxidation process in engineering application, and theoretical guidance is provided for the popularization and application of UV-based AOPs in engineering.

The first technical scheme provided by the invention for solving the technical problems in the prior art is as follows: the method for calculating the optimal adding concentration of the oxidant in the ultraviolet advanced oxidation process based on energy consumption (EE/O) comprises the following steps:

in engineering applications, EE/O is generally composed of two parts: consumption of oxidizing agent (EE/O)_Oxidant) And consumption of electric energy (EE/O)_UV)：

Wherein, P (kWh s)^-1) Is thatEnergy input of the UV lamp, t(s) reaction time, V (L) reaction volume, C_iAnd C_f(M) initial and final concentrations of contaminants, C, respectively_oxidant(mM) adding concentration of an oxidant; alpha (kWh mmol)^-1) Is the conversion coefficient of the oxidant to energy consumption.

1. First, UV/H with only OH as a single PRS₂O₂For example, a calculated UV/H is derived based on EE/O₂O₂The formula of the optimal adding concentration of the oxidant is as follows:

UV/H₂O₂the removal effect on the pollutants in water is determined by the steady-state concentration of OH in the system ([. OH)]_ss)：

In the system [. OH [. ]]_ssUV/H in engineering applications is determined by the Generation Rate (G.R.) of free radicals in combination with the consumption Rate (S.E.) of free radicals₂O₂In the system [. OH [. ]]_ssCan be expressed as:

substituting equations 2 and 3 into equation 1 yields:

wherein beta is the conversion of the output energy of the UV lamp into UV light intensity (I, Einstein. L)^-1·s^-1) The conversion coefficient of (a).

Generally, the EE/O value of the UV-based advanced oxidation process is generally optimized jointly according to the addition concentration of the oxidant and the energy consumption of the ultraviolet lamp. However, in domestic water treatment plants, uv is one of the most widely used disinfection techniques. But for the built water plant, the distribution of the UV lamp tubes and the hydraulic retention time are fixedTherefore, the EE/O value depends mainly on the concentration of the oxidant added. Equation 4 is a function of the addition concentration of the oxidant, and the EE/O tends to increase and then decrease with the increase of the addition concentration of the oxidant. The concentration of the oxidant that produces the smallest EE/O value is the optimum oxidant addition concentration (C) for energy consumption_opt-EE/O). Therefore, equation 4 is derived and set to zero:

in engineering applications, H₂O₂Is generally at a concentration of 10^-3M or less, thus (C)²·β·I·t+2·C³·α)·ε＜＜A_b·C²α, equation 5 can be simplified to

2.303·(A_b·C²α·k_·OH/Oxidant+C²·S_c·α·ε-A_b·I·S_c·β·t)＝0 (6)

And then obtain the calculation C_opt-EE/OThe formula of (a):

2. is popularized to other advanced oxidation processes based on ultraviolet

The invention fits UV/H through a dynamic model₂O₂Different oxidant concentration in the system at a specific treatment process (I ═ 1X 10)^-7Einstein·L^-1·s^-1Hydraulic retention time 300s) [ OH ═ OH-]_ssAnd substituting the formula 4 to obtain the corresponding EE/O value, and the result shows that the corresponding EE/O value is obtained through C_opt-EE/O(formula 7) the minimum EE/O value corresponding to the adding concentration of the oxidant is calculated (figure 1), and the result verifies the accuracy of the formula. Using the same approach, we found that it is based on UV/H₂O₂Derived C_opt-EE/OThe formula (formula 7) can be generalized to other advanced ultraviolet-based oxidation processes (including UV/free oxidation process)Chlorine, UV/persulfate) (fig. 1). For UV/chloramine, (C)²·β·I·t+2·C³A) ε and A_b·C²The value of alpha is an order of magnitude, so equation 5 can be reduced to

2.303·(2·A_b·C²α·k_·OH/Oxidant+C²·S_c·α·ε-A_b·I·S_c·β·t)＝0 (8)

And then obtain the calculation C_opt-EE/OThe formula of (a):

the same kinetic model was used to verify that UV/NH₂And (3) in the Cl system, the EE/O value corresponding to the adding concentration of the oxidant calculated by applying a formula 9 is minimum (figure 1).

In summary, equation 7 (for UV/H) is used₂O₂UV/FAC, UV/PDS) or equation 9 (for UV/NH)₂Cl) can be calculated to obtain the optimal adding concentration (C) of the oxidant based on energy consumption_opt-EE/O)。

Has the advantages that:

the invention has the beneficial effects that:

1) the invention provides a method for calculating the optimal adding concentration of an oxidant in an ultraviolet advanced oxidation process based on energy consumption (EE/O), and the optimal adding concentration of the oxidant which generates the minimum energy consumption (EE/O) in the ultraviolet advanced oxidation process can be measured by using a formula obtained by deducting the method, so that guidance is provided for the application of the ultraviolet advanced oxidation in the aspect of water treatment.

2) Calculation C derived by the invention_opt-EE/OThe formula (A) can be popularized and applied to other ultraviolet-based advanced oxidation processes (such as UV/FAC, UV/PDS, UV/NH)₂Cl) provides a simple method for the engineering energy consumption optimization.

3) The invention deduces and obtains a formula for calculating the optimal adding concentration of the oxidant based on EE/O, and provides a simple method for comparing different ultraviolet advanced oxidation processes.

Drawings

FIG. 1 is a graph showing the change in EE/O values for different oxidants.

Detailed Description

The invention is further illustrated by the following specific examples and the accompanying drawings. The examples are intended to better enable those skilled in the art to better understand the present invention and are not intended to limit the present invention in any way.

Example 1

The invention is further illustrated by way of example with reference to the accompanying drawings.

In this embodiment, a lake water/river water sample is selected, and the C of the water sample in different ultraviolet advanced oxidation processes is determined by a formula with the odor pollutant Geosmin (GSM) common in water as a target pollutant_opt-EE/OThe method comprises the following specific steps:

1) lake/river water samples were passed through 0.45 μm aqueous membrane filters for use.

2) Measuring A of water sample by using ultraviolet spectrophotometer_b(cm^-1) Respectively 0.13.

3) S of water sample measured by experiment_c(s^-1) Are respectively 3.39 multiplied by 10⁵。

4) Obtaining H by consulting a reference₂O₂、FAC、NH₂Molar absorptivity of Cl and PDS ε (M)^-1·cm^-1) 18.6, 62, 382, 22 respectively.

(5) Obtaining H by consulting a reference₂O₂、FAC、NH₂Second order reaction Rate constant k (M) of Cl, PDS and. OH^-1-s^-1) Respectively as follows: 2.70X 10⁷、2.00×10⁹、5.10×10⁸、1.40×10⁷。

(6) Alpha (2.27X 10) is obtained by consulting literature and calculating^-4H₂O₂、6.03×10^-4FAC、1.19×10^-3NH₂Cl and 1.64X 10^-3PDS，kWh·mmol^-1) (ii) a β is 0.523.

(7) Reference is made by the literature to GSM and OH, Cl and SO₄ ^-Respectively have a second-order reaction rate constant of 1.10X 10¹⁰、2.74×10⁹、9.99×10⁸M^-1·s^-1

(8) Substituting the values into formulas 7 and 9 to obtain the water sample H₂O₂、FAC、NH₂The optimal adding concentration of the Cl and PDS based on energy consumption is 5.56 multiplied by 10^-4、3.17×10^-5、4.72×10^-5、2.14×10^-4M, their corresponding EE/O is 7.13X 10 respectively^-3、8.07×10^-3、1.40×10^-2、2.86×10^-2kWh·L^-1。

The results of this embodiment are as follows:

respectively calculating the optimal adding concentration of the oxidant of the selected water sample in different ultraviolet advanced oxidation processes according to a formula, as shown in figure 1: the optimal adding concentration of the oxidant in different ultraviolet advanced oxidation processes for the same water sample generally follows the following rule: HOCl < NH₂Cl＜PDS＜H₂O₂。

It should be understood that the embodiments and examples discussed herein are illustrative only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims.