The invention discloses a method for testing chemical oxygen demand of a water sample through a bichromate method The method comprises: in a highly acid solution, accurately adding an excess potassium dichromate standard solution; performing heating reflux to oxidize substances (mainly including organic matters) with reductibility in the water sample; taking ferroin as an indicator; performing back-dropping on the excess potassium dichromate through an ammonium ferrous sulfate standard solution; and calculating the chemical oxygen demand of the water sample according to the consumed amount of the potassium dichromate standard solution The method is important and can quickly test organic pollutant parameters, and is be conducive to evaluate a polluted condition and a self-cleaning condition of water

Method for testing chemical oxygen demand of water sample through bichromate method

The invention relates to a portable bottle agent suitable for oil-production-platform high-chlorine-root domestic-wastewater-COD rapid detection and a preparing method thereof. The portable bottle agent comprises a wastewater-sample pretreatment bottle agent and a wastewater-sample-analysis-chemical bottle agent; the wastewater-sample pretreatment bottle agent is prepared from a concealing agent and digestion liquid, wherein the concealing agent is 0.3 g/mL of a mercury sulfate solution; the digestion liquid is prepared from 0.098 g/mL of potassium dichromate, 0.50 g/mL of aluminum potassium sulfate and 0.10 g/mL of ammonum molybdate; the wastewater-sample-analysis-chemical bottle agent is 0.088 g/mL of a sulfuric acid-silver sulfate solution. The preparing method of the portable bottle agent includes the step that the concealing agent, the digestion liquid and a catalyst are separately prepared according to dosing respectively. The portable bottle agent is convenient to use, the preservation time of the chemical is long, the analytical precision is good, the portable bottle agent is extremely suitable for detection of an ocean oil production platform, the operation and self-inspection requirements for guiding site high-chlorine-root domestic-wastewater treatment facilities are met, and the aim of analyzing the convenience of chemical transportation is achieved.

Portable bottle agent suitable for oil-production-platform high-chlorine-root domestic-wastewater-COD rapid detection

The invention relates to an accurate, energy-saving and consumption-reduction method for measuring COD (chemical oxygen demand). The method comprises the following steps: preparing potassium dichromate standard solution with the concentration of 0.25mol/L; preparing ferroin indicator solution; preparing ammonium ferrous sulfate solution; preparing sulfuric acid-silver sulfate solution; calibrating the ammonium ferrous sulfate solution, namely, drawing 1mL of potassium dichromate standard solution, adding with water for dilution until reaching 20mL, adding with 3mL of concentrated sulfuric acid, adding with one drop of ferroin indicator solution, placing the ammonium ferrous sulfate solution into a seat type micro burette for titration; weighing 0.04g of mercury sulfate, adding into a HACH transparent threaded pipe, adding with 2mL of water sample, adding with 1mL of potassium dichromate standard solution and 3mL of sulfuric acid-silver sulfate solution simultaneously and placing into a HACH digestion apparatus; performing titration experiment, namely, cooling the solution in the HACH transparent threaded pipe to be at room temperature, transferring the solution into a 50mL conical flask and diluting to reach 20mL with deionized water, adding with one drop of ferroin indicator solution, and titrating with the seat type micro burette, therefore, the COD measurement can be finished. The method is accurate, convenient, safe and environmentally friendly.

Yang Bin

Papers

Accurate, energy-saving and consumption-reduction method for measuring COD (chemical oxygen demand)