Effectiveness of activated zeolite adsorber in decreased soot emission and increased oxygen concentration from combustion smokes of polyvinyl chloride plastic

Polyvinyl Chloride plastic waste is becoming an increasingly urgent global environmental issue. Combustion PVC plastic waste can have significant negative impacts on human health. To overcome these problems, this research was conducted by utilizing zeolite as an adsorbent for PVC combustion smokes. The research methodology is zeolite activation, adsorber design and gas adsorption process through dry adsorption method which is the core of this research. This study will evaluate oxygen concentration and soot emissions. Before being given a zeolite adsorbent, the oxygen concentration produced in PVC combustion smokes was only 17.2% with high soot levels as evidenced by the blackened smoke color. Furthermore, after being given an adsorbent in the form of activated zeolite as much as 283.5 grams, the oxygen concentration produced increased significantly to 20.9% followed by a decrease in soot emission levels as evidenced by changes in the color of whitened smoke. Based on the test results related to the increase in oxygen concentration and the decrease in soot emission levels, it can be concluded that activated zeolite has a high effectiveness in carrying out the PVC combustion smoke adsorption process by producing particles of carbon and oxygen within the normal threshold in the air.


Introduction
Waste is a problem that is widely discussed and is quite difficult to overcome because people's habits tend to be wrong in responding to it.Plastic waste is one of the wastes that is difficult to decompose in nature so that it accumulates and becomes an environmental problem [1].According to data by the Ministry of Environment and Forestry, in 2020 Indonesia produces around 67.8 million tons of waste per year.According to research that has been conducted by several researchers, around 50.1% of Indonesians prefer to manage waste by burning it, 49.9% others throw it into rivers and sewers, bury it in the ground, and there are many more discrepancies in managing waste [2].
One of the most common types of waste is plastic waste.PVC is one type of plastic that is often used because it has many functions, especially in household needs, such as cable insulation materials, piping, and so on [3].However, this type of waste is classified as the most difficult plastic waste to recycle based on its physical properties [4].People prefer to manage PVC or other types of waste by burning, but this process is a dangerous method because [5] burning PVC will produce dioxin or chlorine gas (Cl2), CO and CO2 gases as well as particulate emissions (soot) [6], and if given improper heat treatment will result in very fatal damage to the installation due to the corrosive nature of the gas produced [7].If one breathes air contaminated with these gases, the negative impact on the body's health will become very apparent.It can affect the respiratory system, cause decreased vision, and reduce brain function.Even more seriously, this situation can be fatal with life-threatening consequences [8].PVC plastics also have higher levels of soot emissions and black solid residue than other plastics [9].The black carbon (soot) from burning plastic waste contributes greatly to environmental problems and greatly affects climate change and air pollution in the environment.Efforts to reduce the amount of plastic waste have been made in various parts of the world, especially waste that will end up in the sea.From March 2019 to 2021, a law banning the use of single-use plastic items has been approved by the European Union [10].
Therefore, it is necessary to carry out innovations [11] to overcome this problem, such as innovations in filtering combustion smoke resulting from burning plastic waste.Innovations made to smoke filtering have an important role in life, namely the production of a clean and healthy environment that is free from harmful gases from combustion fumes, vehicles, and factories.This research uses an experimental adsorption method through three stages, namely zeolite activation, designing a series of adsorber devices, and the gas absorption process which is the core stage of this research.Activation of zeolite is very important because the zeolite used will be free from impurities and improve the character of zeolite [12,13].
Through data collection and quantitative analysis, this study aims to reduce gas emissions from PVC plastic combustion that are harmful to health.By chemically activating zeolite, it is expected to reduce gas levels from PVC combustion to normal threshold gases.Based on research [14] It is explained that natural zeolite is able to absorb gas emissions from gasoline motorbike engines in branded motorbikes, and that it is used as a tool to absorb smoke gas emissions in gasoline-burning motorbikes.Numerous investigations have been conducted on PVC plastic combustion products.The characterization of particulate (soot) emissions from burning polymers, including polyvinyl chloride (PVC) plastics, is the subject of this experimental investigation.The findings demonstrate that for each of the five burned plastics, including PVC plastic, the yield and size distribution of the released soot differ significantly.As the bulk equivalency ratio increased, so did the soot yield.PVC particulate emissions are significantly reduced when these materials are burned with excess oxygen.Burning PVC in strongly fuel-lean conditions-that is, with lots of excess air and efficient mixing-is essential to reducing soot emissions.[15].Yanyan Zou et al. [16] this study examines how chlorinated compounds migrate and change as the PVC-CaCO3 composite cable outer sheath burns at various O2 concentrations.Soot is a byproduct of incomplete combustion that is bad for the environment and people's health.The management of soot generation in combustion systems has received a lot of attention in the last few decades.Soot is created by a difficult chemical and physical process.A fundamental understanding of the physical and chemical processes that convert fuel into soot particles in flames is necessary for any attempt to reduce soot emissions.[17].
Additional research has demonstrated that PVC combustion can be safely done with the right pollution control equipment.[18,19,20,21].Di Wu et al. [22] Around the world, uncontrolled burning is a popular method for "permanently eliminating" plastic waste.According to this observation, burning plastic waste on the ground releases harmful aerosols into the air that can be inhaled.These microscopic aerosols, which contain a variety of hazardous species, are extremely dangerous to human health because they are easily inhaled by the body.Previous studies have reported that the open burning of solid waste can directly release hazardous pollutants into ambient air, including particulate matter with an aerodynamic diameter ≤ 2.5 µm persistent organic pollutants, and heavy metals [23].The study PVC can burn with a large number of particles, depending on the combustion conditions.The presence of CO and HCI in PVC products can cause acute inhalation toxicity during and after exposure, and the smoke and haze can impair vision.Inhaling PVC fumes can also cause lung damage because particulates can be drawn in and lodged in the lungs.[24].This study [25] introduces a new material (Oxydtron), which does not contain heavy metals and at the same time an excellent stabilizer and flame retardant agent for PVC, generally, PVC stabilization is done with cadmium or lead (which are heavy metals that can cause toxicity).For the heat affected limiting oxygen index samples showed a significant decrease in the chlorine content in the PVC structure accompanied by considerable stability of the carbon content but the opposite will happen when added Oxydtron to PVC the oxygen percentage was maintained at acceptable levels.On research products of rigid PVC burning under various fire conditions [26] different tactics have been employed to simulate these kinds of small-scale fires.The National Bureau of Standards (NBS) smoke chamber is one example of a closed-box test that attempts to gauge the toxicity of combustion in the atmosphere.Throughout the test, variations in oxygen concentration were noted.First, ignition happened in a combustion that was First Under smouldering and the oxygen concentration significantly decreased it was only 19.5% at that point.Secondly, during well-ventilated combustion, ignition occurs and the oxygen concentration increases to 19.95%And finally flaming reaches a peak, and then subsides in the latter part of experiment.And the oxygen concentration increased significantly to 20.75% at that time.Soot particles represent a significant component of the particulate matter emitted by engines.
These emissions are thought to have an impact on the local climate and contribute to smog.Additionally, adsorbed soot particles are primarily responsible for the harmful effects of soot on human health.Numerous chemical species, including heavy metals, inorganic compounds, and organic species like polycyclic aromatic hydrocarbons, can be found in soot particles.The findings demonstrate that adding oxygenate compounds to a diesel substitute fuel lessens the likelihood that soot particles will form.[27].By using zeolite filters, which can raise the oxygen concentration from low levels to the value of oxygen concentration in the earth's atmosphere, this research seeks to reduce soot in the combustion of PVC plastic.

Material and Methods
The stages in this research include: preparation of tools and materials, activation of zeolite, combustion without filtration, with filtration (zeolite before activation), and with filtration (zeolite after activation), data collection, testing and data processing.

Materials
The materials on this research are zeolite, PVC plastic waste, iron barrels (freyon), distilled water, and NaOH.

Activation of Zeolite
Before carrying out the data collection process, first activate the zeolite, zeolite activation carried out in this study using chemical activation with reference to Sumarni et al. [13].As for the procedure, zeolite with a size of 100 mesh was prepared first by soaking it in distilled water for 24 hours.Then, after soaking, the zeolite was heated/dried in an oven at 120 o C for 3 hours.The zeolite was then activated using NaOH and ultrasonic.
First of all, the zeolite that had been prepared was weighed as much as 20 grams and then mixed into a 100 mL 6M NaOH solution.After mixing, the zeolite was activated by ultrasonic for 1 hour at 60 o C.After the ultrasonic process was complete, the zeolite was rinsed with distilled water until pH 7.Then, the zeolite was in the oven at 110 o C for 4 hours [13].After the activation process was complete, the zeolite was then furnace at 450 o C for 8 hours to maximize the results of activation.
The combustion process was carried out by inserting PVC waste that has been chopped into the combustion device.Then the waste is burned and then 3 data collection processes are carried out: (i) first without filtration, (ii) with zeolite filtration before activation, and (iii) with zeolite filtration after activation.

Gas Adsorption Experiment
Tests were carried out using a gas analyzer sensor 4 in 1 O2 CO H2S LEL Bosean BH-4A Tester with O2 gas detection range limit is 0-30%.
The zeolite as the independent variable work as an adsorber with mass variations compared on a scale of 1:2:3:4:5.This data collection process uses a collection tool in the form of translucent plastic which after being collected, the data can be directly tested with a gas analyzer, and then for comparison of soot content can also be clearly seen the colour difference in the combustion smoke results with these various variations.The gas analyzer test in this research is carried out directly during combustion, where the smoke that has been collected with plastic is then tested using a gas analyzer, as for the gas observed in this research is O2.Before the gas analyzer test is carried out, first the temperature of the smoke is measured, for a safe temperature in this test around 20 0 C.With this test, it can be seen how much difference in the effectiveness of zeolite that has not been activated and after activation.  1, it is clear that there is an increase in the percentage of oxygen content as the mass increases.the adsorption using non-activated zeolite increases the oxygen levels to 20.4%.On the other hand, the adsorption using activated zeolite increased the oxygen level to 20.9% [28].According to Occupational Safety and Health Administration (OSHA), the safe range of oxygen percentage in confined spaces is 19.5-23.5% [29].Oxygen levels in the earth's atmosphere including the Medan city, North Sumatera area are 20.5%.The success in this process is due to the influence of the zeolite activation process because the process carried out has an impact on the polarity of the zeolite.It can also be seen that, before the zeolite adsorber was applied, the O2 content of the PVC combustion smoke was 17.2%, which is very far from the standard O2 content limit in the environment.However, in the research there is a very significant difference in the results of O2 levels of PVC combustion smoke with 2.3 Adsorber Design the addition of adsorbers, where the adsorption results obtained on zeolite without activation with a mass variation of 170.1 gram, 226.8 gram, 283.5 gram and activated zeolite with a mass variation of 113.4 gram, 170.1 gram, 226.8gram, 283.5gram, have successfully met the safe level range.With the highest oxygen content of 20.9% [30] found in the adsorption results of activated zeolite with a mass variation of 283.5 gram.

Soot Content (Colour) of Combustion Smoke Resul
From the results, it can be seen from table 1 that the levels of soot emissions (particulate emissions) or black colour in PVC combustion smoke are more clearly visible in combustion without adsorbers than combustion using adsorbers.This happens because zeolite has the ability to bind soot emissions in PVC waste combustion smoke.

Conclusions
Before being given an zeolite, the oxygen content produced in combustion smoke is only 17.2% and after being given an adsorber in the form of activated zeolite as much as 283.5 grams, the oxygen concentration produced increases significantly to 20.9%.In addition to increasing oxygen concentration, zeolite is also able to reduce soot emission levels in PVC combustion smoke.Where before being given an adsorber, the combustion smoke is blackiah gray and after being given an adsorber in the form of zeolite 283.5 grams of combustion smoke becomes white.

Figure 1 .
Figure 1.Graph of oxygen concentration levels

Table 1
Colour Produced Through Nonactivated Zeolite Adsober and Activated Zeolite Adsober