Leaching of metals from printed circuit board powder by an Aspergillus niger culture supernatant and hydrogen peroxide

RSC Advances ◽  
2016 ◽  
Vol 6 (49) ◽  
pp. 43442-43452 ◽  
Author(s):  
U. Jadhav ◽  
C. Su ◽  
H. Hocheng
Keyword(s):  
Hydrogen Peroxide ◽  
Aspergillus Niger ◽  
Sodium Hydroxide ◽  
Printed Circuit Board ◽  
Culture Supernatant ◽  
Sodium Hydroxide Solution ◽  
Circuit Board ◽  
Printed Circuit ◽  
Hydroxide Solution ◽  
P Removal

Removal of chemical coating of PCB powder using 0.1 M sodium hydroxide solution.

scholarly journals PRODUÇÃO DE CELULASES E XILANASE POR Aspergillus niger IZ9 USANDO FERMENTAÇÃO SUBMERSA SOBRE BAGAÇO DE CANA-DE-AÇÚCAR

2000 ◽  
Vol 18 (1) ◽  
Author(s):  
CLAUDIO LIMA AGUIAR ◽  
TOBIAS J. B. MENEZES
Keyword(s):  
Aspergillus Niger ◽  
Phosphoric Acid ◽  
Sodium Hydroxide ◽  
Sugarcane Bagasse ◽  
Sodium Hydroxide Solution ◽  
Cellulolytic Enzymes ◽  
Hydroxide Solution ◽  
Chemically Treated

Avaliou-se a produção de celulases e xilanase de Aspergillus niger IZ9, crescido sobre bagaço de cana, quimicamente tratado, como substrato. Os tratamentos foram: solução de hidróxido de sódio a 4%, e solução de hidróxido de sódio a 4%, ácido fosfórico p.a. e vapor. A produção das enzimas celulolíticas (celulase total, endoglicanase e ­glicosidase) e xilanase foi observada nos bagaços tratados e nãotratado. O tratamento com solução de hidróxido de sódio a 4% promoveu maior indução de síntese da maioria das enzimas, com exceção de ­glicosidase, a qual apresentou produção semelhante para os bagaços tratados quimicamente. Abstract It was evaluated the production of cellulases and xylanase by Aspergillus niger IZ09 grown in a substrate consisted of chemically treated sugarcane bagasse. The treatments were: 4% sodium hydroxide solution and 4% sodium hydroxide solution, phosphoric acid and steam. The production of the cellulolytic enzymes (total cellulase, endoglycanase and B.CEPPA, Curitiba, v. 18, n. 1, jan./jun.2000 67 ­glucosidase) and xylanase was observed in the treated and nontreated bagasses. The treatment with 4% sodium hydroxide solution promoted a greater induction of the synthesis of the majority of the enzymes, with exception of ­glucosidase, which showed similar production for both chemically treated bagasses.

Scalability of Copper-Interconnects down to 3μm on Printed Boards by Laser-assisted-subtractive process

2019 ◽  
Vol 2019 (NOR) ◽  
pp. 000017-000020
Author(s):  
Sarthak Acharya ◽  
Shailesh Singh Chouhan ◽  
Jerker Delsing
Keyword(s):  
Printed Circuit Board ◽  
Sodium Hydroxide Solution ◽  
Copper Interconnects ◽  
Circuit Board ◽  
Etching Time ◽  
Feature Size ◽  
Printed Circuit ◽  
Disruptive Technologies ◽  
Reverse Mode ◽  
Board Level

Abstract As per the latest roadmap of iNEMI, the global electronics market is emphasizing to identify disruptive technologies that can contribute towards denser, robust and tighter integration on the board level. Therefore, reduction in packaging factor of printed board can accommodate greater number of ICs to support miniaturization. This paper has shown an experimental method to pattern the metallic layer on a Printed circuit Board (PCB) to the smallest feature size. To investigate this, a commercially available FR-4 PCB with photosensitive material coat and a Copper (Cu) layer on it, is used. A reverse-mode Laser assisted writing is implemented to pattern the desired copper tracks. Soon after, a well-controlled development and chemical etching of the Laser-activated regions are done using Sodium Hydroxide solution followed by an aqueous solution of Sodium Persulfate. Current PCB interconnects used by the industries are of the order (~20 μm). Whereas the present work is a contribution towards achieving Copper interconnects with feature size 3.0μm. This miniaturization corresponds to 70% reduction in the feature size from 20 μm to 3 μm. The natural adhesion of the Cu layer has remained intact even after the etching, shows the efficiency of the method adopted. Also, variation in the parameters such as etching time, etchant solution concentrations, temaperature, gain and exposure time of Laser beam and their corresponding effects are discussed. Other highlights of this subtractive method includes its cost-efficiency, lesser production time and repeatability.

scholarly journals Pelarutan Selektif Tembaga dari Limbah Printed Circuit Board dengan Hidrogen Peroksida

2018 ◽  
Vol 14 (1) ◽  
pp. 51
Author(s):  
Gatut Ari Wardani ◽  
Rokiy Alfanaar ◽  
Sri Juari Santosa
Keyword(s):  
Hydrogen Peroxide ◽  
Copper Content ◽  
Printed Circuit Board ◽  
Volume Ratio ◽  
Absorption Spectrometry ◽  
Circuit Board ◽  
Copper Metal ◽  
X Ray ◽  
Printed Circuit ◽  
Optimal Separation

<p>Pelarutan selektif tembaga dari limbah <em>printed circuit board</em> (PCB) telah berhasil dilakukan. Logam tembaga yang terkandung di dalam papan PCB dapat dipisahkan menggunakan campuran hidrogen peroksida dan asam sulfat dengan variasi perbandingan volume 0 : 1, 1 : 1, 2 : 1, 3 : 1, 4 : 1, dan 5 : 1. Pemisahan optimal dilakukan dengan sistem perendaman selama 3 hari dengan campuran H<sub>2</sub>O<sub>2</sub>/H<sub>2</sub>SO<sub>4</sub> = 3 : 1 (v/v). Jumlah tembaga yang terkandung di dalam papan PCB dianalisis menggunakan <em>X-ray fluorescense</em>. Tembaga yang terkandung di dalam PCB sebesar 57,7%. Pelarutan selektif dapat menurunkan kadar tembaga sehingga tembaga yang masih tersisa adalah sebesar 7,7 x 10<sup>-4 </sup>%. Penurunan kadar tembaga yang terkandung di dalam PCB mencapai 99,999%. Analisis spektrometri serapan atom dilakukan untuk mengetahui jumlah tembaga yang terlarut yaitu sebesar 25,415 mg/kg PCB.</p><p><strong>Leaching of Copper from Printed Circuit Board Waste with Hydrogen Peroxide</strong><strong>. </strong>Leaching of copper from printed circuit board (PCB) waste has been successfully performed. The copper metal contained in the PCB can be separated using a mixture of hydrogen peroxide and sulfuric acid with a variation of volume ratio is 0 : 1, 1 : 1, 2 : 1, 3 : 1, 4 : 1, and 5 : 1. Optimal separation is carried out by the immersion system for 3 days using H<sub>2</sub>O<sub>2</sub>/H<sub>2</sub>SO<sub>4</sub> = 3:1 (v/v). The amount of copper contained in the PCB was analyzed using X-ray fluorescence. The copper contained in the printed circuit board is 57.7%. The leaching process can decrease the copper content so that the remaining copper is 7.7 x 10<sup>-4</sup>%. The decrease of copper content contained in PCB reaches 99.999%. Analysis of atomic absorption spectrometry was conducted to determine the amount of dissolved copper that is 25.415 mg/kg PCB.</p>

Characteristics of Radiated Emission from a Printed Circuit Board with a Slit

2012 ◽  
Vol 132 (6) ◽  
pp. 404-410 ◽  
Author(s):  
Kenichi Nakayama ◽  
Kenichi Kagoshima ◽  
Shigeki Takeda
Keyword(s):  
Printed Circuit Board ◽  
Circuit Board ◽  
Printed Circuit ◽  
Radiated Emission

Confirming the Signal Integrity in Transmission of Digital Signals on Microstrip Straight Circuits via the Eye Diagrams

2014 ◽  
Vol 5 (1) ◽  
pp. 737-741
Author(s):  
Alejandro Dueñas Jiménez ◽  
Francisco Jiménez Hernández
Keyword(s):  
Integrated Circuits ◽  
Printed Circuit Board ◽  
Signal Integrity ◽  
High Volume ◽  
Information Storage ◽  
Circuit Board ◽  
Electromagnetic Simulation ◽  
Electronic Systems ◽  
Digital Signals ◽  
Printed Circuit

Because of the high volume of processing, transmission, and information storage, electronic systems presently requires faster clock speeds tosynchronizethe integrated circuits. Presently the “speeds” on the connections of a printed circuit board (PCB) are in the order of the GHz. At these frequencies the behavior of the interconnects are more like that of a transmission line, and hence distortion, delay, and phase shift- effects caused by phenomena like cross talk, ringing and over shot are present and may be undesirable for the performance of a circuit or system.Some of these phrases were extracted from the chapter eight of book “2-D Electromagnetic Simulation of Passive Microstrip Circuits” from the corresponding author of this paper.

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