Iman Noshadi

Microwave assisted biodiesel production from Jatropha curcas L. seed by two-step in situ process: Optimization using response surface methodology

The synthesis of fatty acid ethyl esters (FAEEs) by a two-step in situ (reactive) esterification/transesterification from Jatropha curcas L. (JCL) seeds using microwave system has been investigated. Free fatty acid was reduced from 14% to less than 1% in the first step using H2SO4 as acid catalyst after 35 min of microwave irradiation heating. The organic phase in the first step was subjected to a second reaction by adding 5 N KOH in ethanol as the basic catalyst. Response surface methodology (RSM) based on central composite design (CCD) was utilized to design the experiments and analyze the influence of process variables (particles seed size, time of irradiation, agitation speed and catalyst loading) on conversion of triglycerides (TGs) in the second step. The highest triglycerides conversion to fatty acid ethyl esters (FAEEs) was 97.29% at the optimum conditions:<0.5mm seed size, 12.21 min irradiation time, 8.15 ml KOH catalyst loading and 331.52 rpm agitation speed in the 110 W microwave power system.

Efficient biomass transformations catalyzed by graphene-like nanoporous carbons functionalized with strong acid ionic liquids and sulfonic groups

Strong acid ionic liquids and sulfonic group bifunctional graphene-like nanoporous carbons (GNC-SO3H-ILs) have been synthesized by treating nitrogen containing graphene-like nanoporous carbons (GNCs) with 1,3-propanesultone, ion exchanging with HSO3CF3 or H2SO4. Introducing nitrogen is important for grafting strong acid ionic liquids and sulfonic group in GNCs, which were synthesized from carbonization of a mixture of dicyandiamide or melamine and glucose. GNC-SO3H-ILs possess abundant nanopores, nanosheet structure, good dispersion and controlled acidity. By themselves, they are capable of enhancing the fast diffusion of reactants and products, while increasing the exposure degree of acidic sites in GNC-SO3H-ILs throughout various reactions. The above characteristics resulted in their much improved catalytic activity in biomass transformations such as the production of biodiesel and depolymerization of crystalline cellulose into sugars, which was even comparable to those of homogeneous ionic liquid and mineral acids.

Swelling behaviour and controlled drug release from cross-linked -carrageenan/nacmc hydrogel by diffusion mechanism

We studied a model system of controlled drug release using beta-carotene and κ-carrageenan/NaCMC hydrogel as a drug and a device, respectively. Different concentrations of genipin were added to crosslink the beta-carotene loaded beads by using the dripping method. Results have shown that the cross-linked beads possess lower swelling ability in all pH conditions (pH 1.2 and 7.4), and swelling ratio decreases with increasing genipin concentration. Microstructure study shows that cross-linking has enhanced the stability and structure of the beads network. Determination of diffusion coefficient for the release of encapsulated beta-carotene indicates less diffusivity when beads are cross-linked. Swelling models using adaptive neuro fuzzy show that using genipin as a cross-linker in the kC/NaCMC hydrogels affects the transport mechanism. The model shows very good agreement with the experimental data that indicates that applying ANFIS modelling is an accurate, rapid and simple way to model in such a case for controlled release applications.

Purification of biologically treated Tehran refinery oily wastewater using reverse osmosis

Abstract In this paper, results of an experimental study on separation of oil from industrial oily wastewaters with combined biologically method/reverse osmosis (RO) process for purification of Tehran refinery oily wastewater is presented. The effects of different operating parameters on permeation flux and TDS rejection were investigated. Taguchi method (L9 orthogonal array (OA)) was used initially to plan a minimum number of experiments. Analysis of variance (ANOVA) was applied to calculate sum of square, variance, ratio of factor variance to error variance and contribution percentage of each factor on response. The results showed that TMP and temperature have significant effects on the response. Permeation flux was found to increase with increasing transmembrane pressure (TMP), cross flow velocity (CFV) and feed temperature at constant feed concentration but rejection slightly decreases. The pH effects were found to be complex. By increasing acidic and basic nature of the feed, permeation flux was foun...

Transesterification Catalyzed by Superhydrophobic–Oleophilic Mesoporous Polymeric Solid Acids: An Efficient Route for Production of Biodiesel

We report here an efficient mesoporous polymeric solid acid catalyst (p-PDVB-SO3H) with superhydrophobic–oleophilic properties synthesized from copolymerization of divinylbenzene (DVB) with sodium p-styrene sulfonate under solvothermal conditions. N2 isotherm showed that p-PDVB-SO3H has large BET surface area and uniform mesopore. Contact angle tests showed that p-PDVB-SO3H exhibits superhydrophobic–oleophilic property for triolein and methanol, which results in its good miscibility and high exposition degree of active sites for various organic reactants. Catalytic tests showed that p-PDVB-SO3H has much better catalytic activities and recyclability toward transesterification to biodiesel than those of H-form mesoporous ZMS-5 zeolite, carbon solid acid and commercially acidic resin of Amberlyst 15, which will be very important for its wide applications for biodiesel production in industry.Graphical AbstractSuperhydrophobic–oleophilic mesoporous solid acid of p-PDVB-SO3H exhibits very good wettability for methanol and plants oil, further leading to its high exposition degree of active sites, which results in its excellent catalytic activity toward transesterification to biodiesel.

Superhydrophobic and stable mesoporous polymeric adsorbent for siloxane removal: D4 super-adsorbent

Synthesis of a new class of siloxane adsorbent (D4) was done to purify methane-rich gases including biogas and digester gas, at near ambient temperature and atmospheric pressure. The nanoporous polymeric adsorbent with controlled wettability was successfully prepared under solvothermal conditions. Imidazole groups were introduced into the samples by copolymerization of divinylbenzene (DVB) with 1-vinylimidazole (VI). The copolymer composition was varied to obtain optimum adsorption performance. Low-cost PDVB and PDVB-VI were evaluated under different adsorption conditions with a gas flow rate of 10 mL min−1. To simulate near real time biogas composition, 50%-relative humidity at 25 °C was maintained to assess the effect of humidity on D4 removal efficiency. In addition, the mixture gas was used to evaluate the adsorptive activity in the presence of CO2 (up to 35%). While PDVB alone demonstrates a significant adsorption activity with a capacity of 1951 ± 74 mg g−1, an improvement in adsorption capacity to 2370 ± 92 mg g−1, was noted with PDVB-VI. Characterization of exhausted adsorbent demonstrates the correlation between D4 adsorption and PDVB-VI-x textural properties. Finally, PDVB-VI-x was readily regenerated after five cycles with less than 10% loss in adsorption activity under both dry and humid conditions.

Hydrophobic mesoporous adsorbent based on cyclic amine–divinylbenzene copolymer for highly efficient siloxane removal

This paper presents a new class of octamethylcyclotetrasiloxane (D4 siloxane) adsorbent based on the copolymer of divinylbenzene and a novel methacrylate monomer. The novel cyclic amine based methacrylate monomer was synthesized employing click chemistry and was polymerized to form a mesoporous adsorbent under solvothermal conditions and tested for siloxane removal. The D4 adsorption capacity of the novel adsorbent is 2220 mg g−1, which is greater than the adsorption capacities of mesoporous poly(divinylbenzene) and commercial activated charcoal. The adsorbent retains 47% regeneration capacity after 10 usage cycles. The high specific adsorption is due to a combination of physisorption, caused by the mesoporosity and pore volume and chemisorption, as evidenced by spectroscopic results. The incorporation of functional groups into a mesoporous structure with significantly enhanced specific adsorption offers future opportunities towards tailored polymer properties for efficient industrial applications in siloxane removal.