Life cycle assessment perspective on waste resource utilization and sustainable development: A case of glyphosate production.

The growing demand for pesticide manufacturing and increasing public awareness of sustainable development, have let to urgent requirements for a refined environmental management framework. It is imperative to conduct process-based life cycle assessments (LCAs) to promote clean and environment-friendly technologies. Herein, the cradle-to-gate LCA of glyphosate production was executed as an example to investigate crucial production factors (materials or energy) and multiple environmental impacts during the production processes. Results showed that methanol caused the highest environmental damage in terms of toxicity, with a normalized value of 85.7 × 10-8, followed by coal-fired electricity in 6.00 × 10-8. Furthermore, optimized schemes were proposed, including energy improvement (electricity generated by switching from coal-fired power to solar power) and wastewater targeted conversion. Regarding the normalization results before and after optimization, the latter showed more significant results with the normalized value decreasing by 21.10 × 10-8, while that of the former only decreased by 6.50 × 10-8. This study provides an integrated LCA framework for organophosphorus pesticides (OPs) from upstream control and offers an important supplement to managing the key pollution factors and control links of the OP industry. Moreover, it reveals the positive influence of optimized schemes in facilitating cleaner production technologies, thus ultimately promoting new methodologies for resource recycling.

[Microbial reduction of Fe(III) (EDTA) in the system of nitric oxide removal by metal chelate absorption].

Reduction of Fe(III) (EDTA) with cultivated microorganisms in the system of nitric oxide removal by metal chelate absorption was investigated. Supplemental glucose stimulates the formation of Fe(II) (EDTA) more than ethanol and methanol as the carbon sources. Ammonium salt was used to be as the nitric source instead of nitrate, which inhibits the reduction of Fe(III) (EDTA) due to the competition between the two electron acceptors. The optimal pH value was from 6 to 7. The reduction percentage of Fe(III) (EDTA) varied little with the range of 30 degrees C - 40 degrees C and decreased quickly with a temperature higher than 40 degrees C. The bio-reduction could be achieved efficiently with enough carbon source and cell inoculation. The reduction rate did not increase with adding more amount of carbon source or cell inoculation. The bio-reduction rate could be described by Michaelis-Menten equation and fitted to the first order reaction kinetics. The maximum reaction rates gamma max and the Michaelis constant k(m) were 1.3 mmol x (L x h)(-1) and 53.5 mmol x L(-1)respectively.

Dissimilatory reduction of FeIII (EDTA) with microorganisms in the system of nitric oxide removal from the flue gas by metal chelate absorption.

In the system of nitric oxide removal from the flue gas by metal chelate absorption, it is an obstacle that ferrous absorbents are easily oxidized by oxygen in the flue gas to ferric counterparts, which are not capable of binding NO. By adding iron metal or electrochemical method, FeIII(EDTA) can be reduced to FeII(EDTA). However, there are various drawbacks associated with these techniques. The dissimilatory reduction of FeIII(EDTA) with microorganisms in the system of nitric oxide removal by metal chelate absorption was investigated. Ammonium salt instead of nitrate was used as the nitrogen source, as nitrates inhibited the reduction of FeIII due to the competition between the two electron acceptors. Supplemental glucose and lactate stimulated the formation of FeII more than ethanol as the carbon sources. The microorganisms cultured at 50 degrees C were not very sensitive to the other experimental temperature, the reduction percentage of FeIII varied little with the temperature range of 30-50 degrees C. Concentrated Na2CO3 solution was added to adjust the solution pH to an optimal pH range of 6-7. The overall results revealed that the dissimilatory ferric reducing microorganisms present in the mix-culture are probably neutrophilic, moderately thermophilic FeIII reducers.