Removal of Rhodamine-B by biogas waste slurry from aqueous solution

The ability of biogas waste slurry to adsorb a basic dye (Rhodamine-B) has been investigated. The parameters include agitation time, initial dye concentration, pH and adsorbent dosage. The rate controlling step is mainly intraparticle diffusion. The adsorption rate constant was found to be 2.9 × 10^?2 min^?1 at 20 mg L^?1 initial dye concentration. The adsorption conforms with Freundlich isotherm. Removal of the dye was at least 90% in the entire pH range from 2.3 to 11.2. Desorption of the dye in 50% (v/v) acetic acid to the extent of 69.7% indicates that most of the dye is held by the adsorbent by chemisorption.     

Influence of seed position within the fruit on seedling quality and in vitro shoot tip production of jackfruit

This study reports on the influence of seed position within the fruit and shoot development on the production of jackfruit in vitro. Seeds were extracted from the different sections in the fruit and shoot tips excised from the resultant seedlings. The tips were cultured in vitro on media supplemented with 6-benzylaminopurine (BAP) or thidiazuron (TDZ). The seeds from the middle and basal sections of the fruit were larger and produced larger seedlings than those from the top. Seeds from the basal position took 10 days to germinate and produced seedlings 11 cm tall with four or five leaves. Partially covered and fully open shoots from 6–8 week-old seedlings performed best. The highest frequency of shoot induction (100%) and multiple shoot production (7.31 ± 1.2) with a mean length of 3.6 ± 0.13 cm was observed on Murashige and Skoog (MS) media supplemented with 3.0 mg/L BAP. Driver and Kuniyuki (DKW), and MS media were equally effective in shoot multiplication. More than 80% of the rooted plants survived culture, indicating that this technology could be used to conserve wild germplasm.     

Removal of paraquat by adsorption on ‘waste’ Fe(III)/Cr(III) hydroxide: Adsorption rates and equilibrium studies

The ability of ‘waste’ Fe(III)/Cr(III) hydroxide to adsorb paraquat has been investigated. Effects of contact time, initial concentration and pH, adsorption capacity and desorption have been studied. Adsorption followed a first-order expression. The adsorption rate constant decreased from 1–84 to 0–50 min^?1 with the increase of paraquat concentration from 10 to 40 mg litre^?1. Adsorption obeyed the Freundlich isotherm and the K₁ value was found to be 0.1995. A maximum removal of 93% was attained at pH 1204. Desorption with water occurred to the extent of 39% indicating that physical sorption was partly responsible in the adsorption process.