Mineral oil regeneration using selective molecular sieves as sorbents

Microporous molecular sieves are investigated as effective, environmentally safe and cost effective materials for purification of lubricants in late stages of oxidation and also as an alternative to traditional anti-oxidant additives. Molecular sieve crystals with LTL- and BEA-type structures with variable morphology and silica content are used to trap oxidation by-products. It has been found that the aluminum content and the type of charge balancing cations in the molecular sieves play an important role on the amount of organic adsorbed due to a higher affinity of strong Brønsted acid sites and surface cations to hydrocarbons and carbonyl moieties. High selectivity of the molecular sieves towards oxidation products was achieved without influencing additive compounds in the oxidized oil, and thus results in high degrees in oil purification up to 90% depending on the oil formulation. The influence of treatment factors such as temperature, treatment time, solid content and type of oil were investigated. The sorption properties of two different molecular sieves capable of removing selectively the oxidation products, and thus effectively leading to purification in the early and late stages of oxidation, but also to slow down the oxidation process of oils are demonstrated. The considered molecular sieve materials are environmentally safe, cost effective, and due to their high thermal stability are adequate for recovery and multi-cycle reuse.

Removal of emulsified food and mineral oils from wastewater using surfactant modified barley straw

Barley straw, an agricultural waste, was chemically modified and evaluated for the removal of emulsified oils from aqueous solution. The chemical modification was performed using NaOH and a cationic surfactant, hexadecylpyridinium chloride monohydrate (CPC). The surface textural and chemical properties of the surfactant modified barley straw (BMBS) were characterized by N(2) adsorption, FT-IR, SEM and water soluble mineral content. The adsorption tests were carried out in batch adsorption system for removal of standard mineral oil (SMO) and canola oil (CO) from water. For both emulsified oils in wastewater, adsorption was found to be strongly related with solution pH. The isotherm study indicated that emulsified oil adsorption on BMBS could be fitted well with the Langmuir model other than Freundlich model. The maximum adsorption capacity for CO and SMO at 25 degrees C determined from the Langmuir isotherm is 613.3 and 584.2 mg g(-1), respectively. Desorption tests in water solution show that oil is strongly bonded with adsorbent and desorption is only about 1-2% in 24 h.

Treatment of oily waters using vermiculite

The main objective of this study was to examine the removal of oil from water by expanded and hydrophobized vermiculite. A pH of 9 showed a higher removal efficiency of oil by vermiculite. Oil removal efficiencies at pH 9 were found to be 79%, 93%, 90%, 57% for standard mineral oil (SMO), Canola oil (CO), Kutwell oil (KUT45), refinery effluent (RE), respectively, in the case of expanded vermiculite, and 56%, 58%, 47%, 43% for SMO, CO, KUT45 and RE, respectively, for hydrophobized vermiculite. Kinetic data satisfied both the Lagergren and Ho models. Equilibrium studies showed that the Langmuir isotherm was the best-fit isotherm for oil removal by both expanded and hydrophobized vermiculite. The data showed a higher adsorptive capacity by the expanded vermiculite compared to the hydrophobized vermiculite. Desorption studies showed that the expanded vermiculite did not desorb oil to the same extent compared to hydrophobized vermiculite. The Freundlich isotherm was the best-fit model for desorption. Expanded vermiculite showed better retention than hydrophobic vermiculite. The results showed that the expanded vermiculite had a greater affinity for oil than hydrophobized vermiculite.