PREPARATION METHOD OF MN3O4/AG3PO4 COMPOSITE FOR PHOTOCATALYTIC DYE DEGRADATION AND AGRICULTURAL REU

Abstract

The invention presents a novel Mn304/ Ag3P04 composite for efficient photocatalytic degradation of organic dyes in wastewater. Synthesised via a simple chemical precipitation method, this composite integrates the stability of Mn304 with the remarkable photocatalytic efficiency of AgsP04- and eliminates common issues like electron-hole recombination and photo-corrosion. The composite highlights exceptional degradation efficiencies, achieving 98% degradation of Methylene Blue, 81% for Rhodamine B, and 92% for Sunset Yellow in 25 minutes. Additionally, the treated water promotes the growth of Vigna radiata (mung beans), accentuating its potential for safe agricultural reuse. Initially, the plant grown in untreated water showed a growth rate greater than that in treated water, but after 7 days of growth, the plant in untreated water degraded due to the accumulation of dye molecules in the stem. Thus, treated water proved an efficient growth of plants, making it suitable for agricultural use. This invention provides a scalable and affordable environmental remediation solution extremely suited to wastewater treatment.

Specification

FIELD OF THE INVENTION
[0001) The present invention relates to the tield of photocatalysis and environmental remediation.
More specifically, it pertains to a novel Mn,O./Ag,PO. composite material developed for the
efficient photocatalytic degradation of organic dyes in wastewater. The invention encompasses the
synthesis process of combining Mn,O. and Ag,PO. nanoparticles to create a stable, highly
effective photocatalyst aimed at environmental cleanup applications.
BACKGROUND OF THE INVENTION
[0002] Photocatalysis is a promising method for degrading organic contaminants, such as dyes,
in wastewater. Conventional methods for treating wastewater frequently fail to adequately
eliminate these enduring organic components, resulting in notable environmental consequences.
Organic dyes present significant challenges because of their strong durability, toxicity, and
potential to cause cancer, which can have severe consequences for both aquatic life and human
health.
(0003] As photocatalysis continues to be explored for water treatment, there is a critical need to
improve its efficiency and adaptability to large-scale commercial applications. Recent research
focuses on developing innovative materials, such as composite photocatalysis, to enhance the
selectivity and efficiency of photodegradation. Composites combine the beneficial properties of
two or more materials, providing improved characteristics over individual components .
(0004) The main challenge of using a composite material is to get consistent results due to its size
variation and synthesis process. However, in this invention, we have used a simple synthesis
method that helps in the scalable production of the material. Because of their exceptional
photocatalytic characteristics, Mn304 (manganese oxide) and Ag3PO• (silver phosphate) have gained considerable interest as photocatalytic materials. Mn304 is recognised for its stability and
economical nature, but Ag3P04 demonstrates exceptional photocatalytic efficacy when exposed to
visible light. Nevertheless, every material possesses inherent restrictions when employed
individually. The photocatalytic efficacy of Mn304 is generally limited due to the quick
recombination of photo-generated electron-hole pairs. However, Ag3P04, despite its excellent
efficiency, is susceptible to photo corrosion, compromising its stability and long-term usability.
Sheet i
(0005) CN107626331A invention discloses water technology and efficient visible light responses
of Mn304/BiOCl heterojunction photocatalyst. CN 117504903A invention discloses a highefficiency
CDs/ Ag3P04 composite photocatalyst, preparation method, and application.
CNI08325543B invention relates to synthesising activated carbon-loaded petal-shaped silver
phosphate complex-phase photocatalytic material. CN108160091B invention discloses the
synthesis-method of mixed valence state manganese oxide/silver phosphate-photocatalyst for the -
degradation of pollutants in water. CN I 07029761 A invention discloses the preparation method of
the silver-coloured photochemical catalyst of a kind of zinc sulfide compound phosphoric acid.
CN I 07096554A invention relates to the preparation method that a type of cobalt phosphate aids
in silver phosphate photocatalyst and belongs in environmental protection at sewage management
technical fields.
BRIEF DESCRIPTION OF THE INVENTION
(0006) The present invention discloses a novel composite photocatalyst material, Mm04/AgJP04,
developed through a simple and efficient chemical precipitation synthesis method to address the
challenges. The Mm04 component, characterised by a unique pyramid-like structure, is
synthesised via a chemical precipitation method using Mn(CH3C00)2. This pyramid-like Mn304
is subsequently incorporated into the synthesis of AgJP04, which is also prepared using a simple
chemical precipitation method involving AgNOJ and Na2HP04.
(0007) The resulting Mn304/Ag3P04 composite exhibits exceptional photocatalytic properties for
degrading various organic dyes in wastewater. The photocatalytic performance of this composite
. .
was tested on several dye stock samples, including Methylene Blue (MB), Rhodamine B (RhB),
Tetrazine, and Sunset Yellow, covering a range of cationic, anionic, and neutral dyes.
(0008) The Mn304/AgJP04 composite showed remarkable degradation efficiency under visible
light irradiation. Specifically, it exhibited a 98% degradation of MB dye, 81% degradation of RhB,
92% degradation of Sunset Yellow, and 40% degradation ofTetrazine.
(0009) This innovation examines the· impact of photocaialytically treated wastewater on the
germination and growth of Vigna radiata (Mung bean) seeds, using the Mn,O./Ag,PO. composite
photocatalyst, as described in Claim 2. The seeds were cultivated in both treated and untreated
solutions of Methylene Blue (MB). The study revealed that while untreated MB-containing water
initially promoted seed germination within the first 5-7 days, it subsequently hindered growth due
to the residual toxicity of the dye. In contrast, the water treated with the Mn,O./Ag,PO. composite
showed no such adverse effects, resulting in a consistent growth rate comparable to thill observed
in control water (without dye contamination).
(0010) The Mn,O./Ag,PO. composite offers enhanced efficiency, stability, and scalability
compared to individual photocatalysis. The use of this composite material reduces the electronhole
recombination in Mn,o. and prevents the photo-corrosion issues inherent in Ag,PO., resulting
in a synergistic improvement in photocatalytic performance. The scalable synthesis method and
the ability to degrade a wide range of organic dyes further support its potential for commercial
water treatment applications. This innovation highlights the dual functionality of the composite
material-not only in efficiently breaking down toxic dyes in wastewater but also in enabling safe
water reuse for irrigation, thereby addressing environmental and agricultural concerns
simultaneously. The annexed figures give more features and illustrations of the invention,
showcasing typical embodiments and potential uses of this novel photocatalyst.



CLAIM
(0011) We claim
I. A narrow bandgap Ag3P04 is synthesized using a simple chemical precipitation process
and is an excellent material for visible light photocatalysis.
2. i) The bandgap is tailored with the introduction of Mn30 4 to Ag3P04.
ii) The bandgap was tailored from 2.52 eV to 2.13 eV which efficiently absorbs visible
light across the spectrum and effectively degrades contaminated water.
3. The Mm04/Ag:JP04 composite as claimed in claim 2, excels individual Ag3P04 and Mn304
materials by achieving a 98% degradation efficiency for Methylene Blue dye under visible
light irradiation in just 25 minutes.
4. The Mn304/ Ag3P04 composite, as claimed in 2, effectively degraded a variety of dyes,
Sunset Yellow(anionic), Rhodamine B(cationic) and Tetrazine(neutral) with degradation
efficiencies of92%,81% and 40%, respectively, in 25 minutes.
5. The Mm04/Ag3P04 composite, as claimed in claims 2, demonstrates strong reusability
with negligible reduction in photocatalytic efficiency during four consecutive cycles of dye
degradation, sustaining effectiveness throughout numerous uses.
6. The composite material as claimed in 2, improves long-term stability and usability in
photocatalytic processes by reducing photo corrosion.
7. Using the composite as claimed in claim 2, the photocatalytically treated water was suitable
for safe reuse in agricultural irrigations without adverse effects on plant growth.
8. 1 The treated water after photocatalysis using composite Mm04/ AgJP04. as claimed in claim
2, promotes seed germination of Vigna radiata (mung beans). In contrast, untreated water
shows an initial growth rate, but growth gets inhibited due to the presence of dye molecules,
which will inhibit nutrients like carbohydrates, which are essential for plant growth.
9. The method for the production of the composite Mn304/Ag3P04. as claimed in claim 2,
uses a simple chemical synthesis that is adaptable to large-scale commercial application in
environmental remediation.

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