CN-121990670-A - Plant type composite flocculant for removing microplastic and fluoride

CN121990670ACN 121990670 ACN121990670 ACN 121990670ACN-121990670-A

Abstract

The invention discloses a plant type composite flocculant for removing microplastic and fluoride, belonging to the technical field of sewage treatment. The plant type composite flocculant consists of an inorganic coagulant, a polymeric flocculant and a jute water-based extracting solution, and the inorganic coagulant, the polymeric flocculant and the jute water-based extracting solution act on a water body cooperatively through a flocculation-sedimentation process to realize efficient removal of microplastic and fluoride. The jute aqueous extract is prepared by cleaning, drying, crushing and sieving jute raw materials to obtain jute powder, and performing ultrasonic extraction, centrifugation and standing. The invention constructs an inorganic coagulant-polymeric flocculant-plant coagulant aid ternary system, and by introducing the jute aqueous extracting solution as the coagulant aid, the dosage of the inorganic coagulant and the polymeric flocculant in the traditional binary system can be greatly reduced, the synergistic removal rate of microplastic and fluoride in the water body can be obviously improved, and meanwhile, the formed floccules are more compact and easy to settle and separate, and the invention has the characteristics of green, high efficiency and economy.

Inventors

CHEN FEIFEI
LIN LISHAN
LI CHENGMIN
YU YAN
ZHU CHONGBING
LI SHENGJUN
WU XIAOSONG

Assignees

福州大学
爱环吴世（苏州）环保股份有限公司

Dates

Publication Date: 20260508
Application Date: 20260326

Claims (9)

1. A plant-type composite flocculant is characterized by consisting of an inorganic coagulant, a polymeric flocculant and a jute aqueous extract.
2. The plant-type composite flocculant according to claim 1, wherein the inorganic coagulant is at least one of polyaluminum chloride, polyaluminum ferric chloride, polyaluminum sulfate, polyaluminum ferric sulfate, aluminum trichloride, ferric trichloride, and alum.
3. The plant-type composite flocculant according to claim 1, wherein the polymeric flocculant is at least one of polyacrylamide, sodium polyacrylate, sodium polymethacrylate, polyethyleneimine, chitosan, starch, and guar gum.
4. The plant type composite flocculant according to claim 1, wherein the preparation method of the jute aqueous extract is characterized by comprising the steps of firstly cleaning, drying and crushing jute raw materials, sieving with a 40-400 mesh sieve to obtain jute powder, then dispersing 0.3-0.7 g of jute powder in 50-150 mL of water, carrying out ultrasonic treatment for 0.5-3 hours, centrifuging, standing the solution for 12-36 hours, and taking supernatant to obtain the jute aqueous extract.
5. The plant-type composite flocculant according to claim 4, wherein the jute material is at least one of leaves, stems and roots of jute.
6. Use of a plant-type composite flocculant according to any one of claims 1 to 5 for removing microplastic and fluoride from a contaminated water body.
7. The method according to claim 6, wherein the plant-type composite flocculant is dissolved in a polluted water body, the concentration of the inorganic coagulant is 1-500 mg/L, the concentration of the polymeric flocculant is 1-100 mg/L, and the adding amount of the jute aqueous extract is 0.1-2 mL/L.
8. The method according to claim 6, wherein the treatment of the contaminated water body by the flocculation-sedimentation process comprises the steps of adding the plant type composite flocculant to the contaminated water body, rapidly stirring at a rotation speed of 300-500 rpm for 2-5 minutes, slowly stirring at a rotation speed of 50-150 rpm for 5-15 minutes, and then standing for sedimentation for 20-40 minutes.
9. The method according to claim 6, wherein the micro-plastic is at least one of polyethylene, polypropylene, polyethylene terephthalate, polystyrene and polyvinyl chloride, the particle size is 50-500 μm, and the fluoride is at least one of perfluoroalkyl carboxylic acid and perfluoroalkyl sulfonic acid.

Description

Plant type composite flocculant for removing microplastic and fluoride Technical Field The invention belongs to the technical field of sewage treatment, and particularly relates to a plant type composite flocculant composed of an inorganic coagulant, a polymeric flocculant and a jute water-based extracting solution, and a method for removing microplastic and fluoride in a water body by using the flocculant and application of the flocculant. Background At present, the problem of water body composite pollution is increasingly severe, wherein micro plastics and fluoride represented by perfluorooctanoic acid are taken as two typical persistent new pollutants, and have attracted global attention. Microplastic is widely used in sea, river, soil and even drinking water source, has small particle size and large specific surface area, is easy to adsorb organic pollutant and heavy metal, and can be enriched in organism through food chain, thus forming potential threat to ecosystem and human health. Meanwhile, fluoride such as perfluorooctanoic acid is widely applied to a plurality of industrial fields due to extremely high chemical stability and surface activity, so that the fluoride is extremely difficult to degrade in the environment, and has proved to have hepatotoxicity, immunotoxicity and potential carcinogenicity. Therefore, developing a water treatment technology capable of efficiently and economically removing microplastic, fluoride and other composite pollutants in a water body has become a key problem to be solved urgently in the current environmental engineering field. However, existing water treatment technologies face significant challenges in treating these contaminants. Conventional flocculation sedimentation techniques have relied on binary systems consisting of inorganic metal salts (e.g., polyaluminium chloride) and synthetic organic polymeric flocculants (e.g., polyacrylamide). Although the system can effectively remove suspended particles through mechanisms such as electric neutralization, adsorption bridging and the like, the system often exposes the defects of high dosage of the medicament, high treatment cost, limited removal effect on dissolved fluoride and the like when treating the composite pollution of the microplastic and the dissolved fluoride. More importantly, the use of the synthetic flocculant may bring secondary pollution risk, and residual monomers have potential ecological toxicity, so that the green sustainable development of the technology is restricted to a certain extent. To overcome the shortcomings of the traditional methods, researchers have begun to explore the use of natural polymeric flocculants. For example, chitosan derivatives, moringa cationic proteins, etc. have been shown to have a certain flocculation effect on microplastic. However, the biomass materials generally face the bottlenecks of complex extraction process, high preparation cost, difficult mass production and the like, and restrict practical popularization and application. The existing improved patent technology, such as improving the dispersibility of chitosan (CN 120518159A) through physical modification, utilizing a mineral-biological mucus composite system (CN 120903665A) or compounding inorganic salt and organic polymer (CN 119528300A), has the defect of not realizing the efficient removal of various pollutants in terms of process complexity, secondary pollution risk or long-term operation stability although improving flocculation performance to a certain extent. In the aspect of utilizing natural plant materials, partial researches reveal the potential application value of jute. For example, diRui co (CN 107427813A, CN107427745A, et al) discloses the use of crushed jute as a filter aid, but its mechanism of action is mainly due to physical entrapment. A composite adsorption flocculant of jute leaf powder and ferric salt is proposed by China national institute of agricultural science, hemp research institute patent (CN 110142029A). However, the above-mentioned techniques are focused on physical filtration or simply physical mixing, and do not give clear technical suggestion on how to use chemical active components extracted from jute to construct a synergistic system with an inorganic coagulant and a polymeric flocculant, thereby enhancing the removal effect of dissolved pollutants and micro-nano-scale particles at the molecular level. In summary, how to further simplify the process, reduce the medicament consumption and improve the environmental friendliness on the premise of ensuring efficient removal of the microplastic and the fluoride is still a core technical bottleneck facing the current field. Aiming at the above challenges, the invention provides and verifies a new method for constructing an inorganic coagulant-polymeric flocculant-plant coagulant aid ternary synergistic flocculation system by taking jute aqueous extract as a natural synergistic agent for the first time. The system aims to s