A bench-scale integrated process based on submerged aerobic powdered activated carbon-membrane bioreactor (PAC-MBR) has been utilized and established for the treatment of landfill leachate. The results showed that the submerged PAC-MBR system effectively removed biodegradable trace organic compounds by the average removal rate about 71 % at optimum food to microorganism (F/M) ratio of 0.4 gCOD/g day under a HRT of 24 h. Adding nanofiltration (NF) process increased the treatment efficiency up to 99 %. Further, adding powdered activated carbon to activated sludge (AS) resulted in a higher adsorption capacity in comparison with AS. Adsorption isotherms were investigated and fitted by the Langmuir and Freundlich isotherm models in which the Langmuir model performed better. The specific oxygen uptake rate (SOUR) showed that adding PAC reduces the effects of COD on microorganism activities. NH-N, TKN and Heavy metals removal efficiency amounted to 97 ± 2, 96 ± 2, and 99 ± 2 %, respectively.

The purpose of this article is to evaluate the effect of adsorbents and alkali pre-treatment on microorganism activities of activated sludge (AS) for the treatment of landfill leachate (LFL). The chemical oxygen demand (COD) and BOD5/COD ratio of LFL used in this research were 10,500 and 0.68, respectively. In order to survey the role of porous absorbent, perlite was employed as an alternative with low porosity and was compared to powdered activated carbon (PAC), which has been most widely used in the treatment process. As a result, the COD removal efficiency increased from 32% to 47.7% when alkali LFL was loaded to the sequence batch reactors (SBRs) at the optimum conditions of the biological process. Also, at the same condition, both SBRs containing PAC and perlite showed COD removals of over 81% and 72%, respectively. The specific oxygen uptake rate (SOUR) showed that alkali pre-treatment reduces the toxicity effect of heavy metals on microorganism activities. The adsorption capacity (the uptake of COD) was analyzed by Langmuir and Freundlich isotherm models. Further, the kinetic study of COD adsorption during the treatment process demonstrated that the alkali pre-treatment of LFL proceeded faster and was intensified by the presence of adsorbents.

We investigated the adsorption properties of HCN on dianiline (as a model for polyaniline, denoted here as 2PANI) using density functional theory (DFT) by considering the geometry as well as the electronic property. Contact information of 2PANI with HCN at different configurations was studied and the adsorption energy was calculated in each case. UV-vis analysis, density of states (DOS) and natural bond orbital (NBO) analysis were used to study the interaction of HCN with 2PANI at different configurations. Our calculations showed that HCN could be adsorbed on 2PANI with adsorption energy of ∼ −4.3 kcal mol

Studying the interaction of some atmospheric gases (H2O, HCN, NH3, SO3 and H2S) with 3PT oligomers is important in the development of polymeric sensors for gas detection. In the present study, we studied the relaxed geometries, interaction energies, charge analysis, HOMO-LUMO orbital analysis, and UV-vis spectra of all interacted systems using first-principles density functional theory (DFT). All these analyses indicated the potential of polythiophene as an inexpensive polymeric sensor for the analytes mentioned. Interaction energy values of -19.90, -19.66, -14.01, -8.70, and -4.76 kJ mol(-1) were achieved for adsorption of SO3, H2O, NH3, HCN, and H2S on 3PT, respectively. Consequently, clarification of their physical parameters became the major focus of this study.