**1. Introduction**

Zeolite is a crystalline alumino-silicate material that has a micropore structure. The three-dimensional structure of the zeolite is composed of AlO4 and SiO4 which are related to each other by sharing electrons from oxygen and are arranged tetrahedral [1]. Zeolites have been widely used in industrial processes as environmentally friendly heterogeneous catalysts, ion exchange and adsorbents due to their high specific surface area, large pore volume, uniform micropore channels and excellent thermal and hydrothermal stability. The use of zeolite as a catalyst in various industries is limited due to its narrow pores. The reactant components that have a large molecular size will experience difficulties during the mass transfer process which

will affect the catalytic activity [2, 3]. Increasing the diffusion of the reactants on the catalyst can be done by increasing the pore size of the zeolite, or by creating a mesoporous structure on the zeolite. Therefore, the meso-sized catalyst structure is preferred by most industries, especially the petroleum processing industry because it can increase the effectiveness in the petroleum processing process [4].

Researchers [5] have synthesized mesoporous zeolite-Y using a mold in the form of pluronic F127. In general, the mold used is a surfactant that has a long chain. This method has been effective in making of mesoporous zeolite-Y [6].

Mesoporous which is more practical and economical, namely the alkaline treatment known as desilication. This method has been used by many researchers, one of them is researchers [7] that have succeeded in synthesizing mesoporous mordenite using NaOH. Mesoporous distribution in the mordenite increased significantly after being treated with NaOH. This shows that NaOH treatment can produce mesoporous zeolites with a fairly practical and inexpensive process.

The Si/Al ratio in zeolite is one of the characteristics that is closely related to this method of mesoporosity recognition. Alkaline treatment can cause dominant desilication if the Si/Al ratio is above 25 [7]. The low Si/Al ratio value has a limited effect from the alkaline treatment, this is due to the high aluminum content in the zeolite framework, so to get the optimal Si/Al ratio for dominant desilication, the dealumination process needs to be done first. Researchers [8] have succeeded in dealing with H-mordenite, zeolite-Y and ZSM using nitric acid. The dealumination can increase the Si/Al ratio without significantly impairing the crystallinity. In addition, previous study [9] used nitric acid to alluminate zeolite HMCM-22. Nitric acid is considered a strong acid to increase the Si/Al ratio of the zeolite. The dealumiation of mordenite with nitric acid showed an increase in the Si/Al ratio without destroying its crystallinity. This study was conducted by [10].

Mordenite is the most widely used catalyst in industrial processes, one of which is the petrochemical and petroleum process [11]. Mordenite has high thermal stability and is more resistant to acids. Mordenite is also a catalyst with a stronger acid site compared to zeolite-Y [12]. Therefore, mordenite can be used to produce biofuel. One of the raw materials in making biofuel is cellulose.

The research of [13] stated that cellulose is a candidate biomass source with the most potential to replace fossil fuels in the next few years, because it can reduce greenhouse gas emissions than fossil fuels. One type of cellulose polymer is α-cellulose. The α-cellulose polymer has a degree of polymerization above 200 [14]. This causes α-cellulose to be a carbon source that can be converted into biofuel. Α-cellulose can be converted into fuel fractions in the form of hydrocarbons and alcohol by using a pyrolysis process.

However, the pyrolysis process is not effective in producing hydrocarbon and alcohol fractions, this is because bio-oil from pyrolysis is known to have acidic properties, is unstable for heating, and contains many oxygenated compounds [15]. Therefore, one effort that can be done to improve the quality of bio-oil from hydrolyzed α-cellulose is the hydrotreating process. The hydrotreating process can be applied to produce biofuels. This causes the hydrotreating process to become a major concern in the petroleum processing industry because it can produce products that have better selling power and usability [16].

Based on the description above, mordenite modification is carried out by treating HNO3 and/or NaOH. This study examines the effect of HNO3 and/or NaOH treatment on Si/Al ratio, crystallinity and acidity of mordenite and the effect of NaOH treatment on mordenite pore character. Then the activity and selectivity of the catalyst were tested in the hydrolyzed α-cellulose hydrotreating process.
