Boric Acid Cross-linked 3D Polyvinyl Alcohol Gel Beads by NaOH-Titration Method as a Suitable Biomass Immobilization Matrix

Granule-base immobilization of biomass is a potential method for a decent quality granular sludge cultivation. In this study, 3D polyvinyl alcohol (PVA) gel beads were chemically cross-linked via a simple NaOH-titration method. The PVA gel beads’ porous morphology was characterized using scanning electron microscope (SEM) and Brunauer–Emmette–Teller (BET), and their mechanical properties were evaluated by swelling rate and compressive stress tests. When cross-linking time was 10 min, high quality gel beads (P10) were synthesized, which demonstrated a homogeneous porous structure, good swelling rate, and high compressive strength. A mechanism for synthesis of the gel beads was proposed based on the results of Fourier transform infrared (FTIR) and X-ray diffractometer (XRD) analysis. Briefly, the intermolecular hydrogen bonds of PVA were firstly broken by NaOH to generate active bond of O–Na, which easily reacted with B(OH)4− to produce the PVA-boric acid gel beads. P10 showed excellent biocompatibility for anaerobic ammonia oxidation (anammox) biomass’ immobilization. After incubation for three months, well granule-base immobilized sludge on P10 was developed in up-flow reactor. The sludge had high abundance of anammox biomass and was in balance with other functional bacteria. This work provides a simple method for the rapid preparation of 3D PVA gel beads and verifies their potential in granule-base immobilization of biomass.

Potential of Zeolite and Algae in Biomass Immobilization

The interest in utilizing algae for wastewater treatment has been increased due to many advantages. Algae-wastewater treatment system offers a cost-efficient and environmentally friendly alternative to conventional treatment processes such as electrocoagulation and flocculation. In this biosystem, algae can assimilate nutrients in the wastewater for their growth and simultaneously capture the carbon dioxide from the atmosphere during photosynthesis resulting in a decrease in the greenhouse gaseousness. Furthermore, the algal biomass obtained from the treatment process could be further converted to produce high value-added products. However, the recovery of free suspended algae from the treated effluent is one of the most important challenges during the treatment process as the current methods such as centrifugation and filtration are faced with the high cost. Immobilization of algae is a suitable approach to overcome the harvesting issue. However, there are some drawbacks with the common immobilization carriers such as alginate and polyacrylamide related to low stability and toxicity, respectively. Hence, it is necessary to apply a new carrier without the mentioned problems. One of the carriers that can be a suitable candidate for the immobilization is zeolite. To date, various types of zeolite have been used for the immobilization of cells of bacteria and yeast. If there is any possibility to apply them for the immobilization of algae, it needs to be considered in further studies. This article reviews cell immobilization technique, biomass immobilization onto zeolites, and algal immobilization with their applications. Furthermore, the potential application of zeolite as an ideal carrier for algal immobilization has been discussed.

Ecological Assessment of Sludge Biocenosis while Nitrogen Removal

The paper presents the results of studies on increasing the efficiency of wastewater treatment from nitrogen compounds during the re-engineering of sludge bioreactors with the use of contact carriers for biomass immobilization. To assess the contribution of the indicative species of microorganisms involved in the processes of nitrification and denitrification, an analysis of the indices of species diversity by functional zones was carried out. The results of the operation of the bioreactor are given when using reticulate contact carriers in the form of partitions to separate the functional zones. It was noted that the oxidation-reduction potential of the bioreactor in nitrogen increased 1.7 times after re-engineering.

CHARACTERISTICS OF Chlorella sp BIOMASS IMMOBILIZED ON CHITOSAN (Chlo-Kit) FOR ADSORPTION OF CHROMIUM(III) SOLUTION

<p>Properties of biosorbent prepared from biomass of <em>Chlorella </em>sp immobilized on chitosan (Chlo-Kit) have been studied for adsorption of Chromium(III). Chlo-Kit adsorbent prepared by following steps: dissolving chitosan to get hydrogel form, immobilization of biomasson chitosan hydrogel, <em>beads </em>formation and crosslinkingthe adsorbent beads using epichlorohydrin reagent.</p>Characterization using FT-IR spectrophotometry and SEM showed that mechanism of biomass immobilization on chitosan involves electrostatic interactions between the functional groups of such both materials. Biomass immobilized on chitosan (Chlo-Kit) showed the higher stability in acid medium than un-immobilized biomass. Adsorption of Cr(III) metal ion on Chlo-Kit occured at optimum pH of 4-5 and followed well the Langmuir adsorption isotherm model. The adsorption capacity of Cr(III) on Chlo-Kit was 68.965 mg/g, about 91% higher than that on Chlorella biomass

CHARACTERISTICS OF Chlorella sp BIOMASS IMMOBILIZED ON CHITOSAN (Chlo-Kit) FOR ADSORPTION OF CHROMIUM(III) SOLUTION

<p>Properties of biosorbent prepared from biomass of <em>Chlorella </em>sp immobilized on chitosan (Chlo-Kit) have been studied for adsorption of Chromium(III). Chlo-Kit adsorbent prepared by following steps: dissolving chitosan to get hydrogel form, immobilization of biomasson chitosan hydrogel, <em>beads </em>formation and crosslinkingthe adsorbent beads using epichlorohydrin reagent.</p>Characterization using FT-IR spectrophotometry and SEM showed that mechanism of biomass immobilization on chitosan involves electrostatic interactions between the functional groups of such both materials. Biomass immobilized on chitosan (Chlo-Kit) showed the higher stability in acid medium than un-immobilized biomass. Adsorption of Cr(III) metal ion on Chlo-Kit occured at optimum pH of 4-5 and followed well the Langmuir adsorption isotherm model. The adsorption capacity of Cr(III) on Chlo-Kit was 68.965 mg/g, about 91% higher than that on Chlorella biomass