Plastic pollution recycling : A case study of first marine protected area of Pakistan ( Astola Island )

Astola Island is the first marine protected area of Pakistan acknowledged 2017, June 15. It is a rich biodiversity hotspot, Ramsar site inhabiting endangered species like Green turtle, Hawksbill turtle, and Arabian Humpback whale. A saw-scaled Russell’s viper is endemic to Island. Marine ecology of Astola Island is affected by plastic pollution resulting in coral destruction, ocean acidification, global warming, fishing nets blockage, water pollution, and coastal erosion. Zeolite catalyst synthesized from environmentally friendly way by coal fly ash to degrade collected plastic waste from Island into useful products in pyrolysis reactor. The synthesized catalyst functionalized further with three type of organosilane(1) Octyltriethoxysilane(OS),(2)Phenyltriethoxysilane(PS),(3)Vinyltriethoxysilane(VS).Zeoli te functionalize with octyltriethoxy silane (ZO) shows the highest performance in plastic pyrolysis, resulting in lower degradation temperature, low residue and more product formation may be due to having long chain hydrocarbon and acidic sites. Plastic recycling is the promising solution to tackle plastic blooming issue. Which is negatively impacting all the compartments of ecosystem especially marine environment.

Zeolites are crystalline micro porous alumina silicate materials which are stable over a wide range of temperature. Zeolite synthesized from both naturally (e.g. Coal fly ash) and synthetically from pure chemicals. The coal fly ash precursor for zeolite synthesis is environmentally friendly and has major components like Alumina (Al) and silica (Si) (Cuzma et al., 2020). Zeolites are stable up to 650 0 C -1000 0 C mostly containing high silicato-alumina ratios. It exhibits acidity comparatively higher than previous silica-alumina catalyst. Zeolites have both Bronsted and Lewis acid sites. These acidic sites present on zeolite affected by nature, type, density, strength distribution, location and geometric distribution of acidic sites. Synthesis of zeolite by coal fly ash is environmentally friendly way.
Organosilane was used for the surface modification of zeolites (Li et al., 2015).Zeolite modifies or grafted with octyltriethoxy silane (OTEOS) by variable amount because of maximum active sites accessibilty.It also increases hydrophobicity of zeolites. These modify zeolites have several applications (Novak et al., 2020).
Pyrolysis is obtained through different catalytic processes like thermal, hydrocarbon and catalytic. Thermal catalysis has a drawback as; it produces more carbon range products.

Methods and Materials
The study area was visualized through ArcGIS (10.7.1) to select the sampling sites.
Sampling was carried out in March, 2020 and weather conditions were mostly sunny Samples were collected on five different beaches including Ormara, Jabbal Juddi, Jabbal zareen, Pasni creek beach and Astola Island (first marine protected area).The geographical coordinates of sampling site was recorded through global positioning system (GPS). The areas were chosen due to accumulation of plastic waste and garbage. NaOH anhydrous form and grounded into fine powder mixture using a pestle and mortar.
The dried mixture was transferred into a crucible and placed in a furnace at 500°C for 2   All catalysts decreased the initial degradation temperature which is more expressive for the catalyst ZO that is 180 0 C and total reaction time was 63 minutes. The more product formation with ZP catalyst that was 80ml (oil).

Rate of conversion (%) =Initial mass of plastic -Mass of plastic left in the reactor x100
Initial mass of plastic.
It was found that chemical action on plastic waste within the temperature varies 175 0 C -500 0 C depending on • Temperature, • Quantity of catalyst Because of chemical action degradation of plastic waste upon heating, to get 5 kg wax, 10 kg charcoal, 5 kg of gas and maximum 80 ml liquid product. Two type of analysis generally one is physical and other is chemical analysis.

Physical analysis of pyrolysis oil:
• Color of the oil The colors were identified visually, light yellow to orange in color due to different polymer composition.
( Figure. (1) Pyrolysis reactor in which mixture of plastic converted into useful products)

Viscosity of oil:
Viscosity of oil produced from plastic was measured by using Ostwald Viscometer. The viscometer was filled with the oil up to mark .after the suction was done to pull it to the upper reserivor.The suction was removed and the oil was allowed to go back to the lower reservoir. During this movement from upper to lower mark on each reservoir, the time was measured using stopwatch. Water was used as a reference material for the viscometer as its density is well-known and calculated relative viscosity of the oil by using Oswald equation. applied. TGA studies showed that without catalyst more residues left but with the addition of zeolite catalyst having different organo silane modifications are fewer residues and more product formation. Zeolite without functionalization exhibited a lower degradation rate compared to others, so ZO showed higher catalytic activity may be associated with the greater number of strong acidic sites.

Conclusion
The synthesized catalyst ZO showed the highest performance in plastic pyrolysis, resulting in lower degradation temperature, low residue and more product formation might be due to having long chain hydrocarbon and acidic sites. This is the first study to focus on plastic pollution in Astola Island. Recycling of plastic is the most promising solution to conserve biodiversity of all ecosystems especially marine environment. This research recommends proper waste management plan implementation in Astola Island because there is no management plan yet.